Method for preparing cyclobutene skeleton compound through visible light catalysis

Abstract

The invention discloses a method for preparing a cyclobutene skeleton compound through visible light catalysis. The invention specifically discloses a preparation method of a cyclobutene compound, which comprises the following step: in a solvent, in the presence of a photocatalyst and under the irradiation of visible light, carrying out cyclization reaction on a conjugated diene compound I to obtain a cyclobutene compound II. According to the preparation method, a cheap catalytic system is adopted, the reaction condition is mild, the electro-cyclization reaction of the conjugated diene compound can be efficiently realized, and the preparation method has good functional group compatibility, substrate applicability and atom economy and meets the development requirements of green chemistry. In addition, the method needs a small amount of a photocatalyst, the reaction process is simple and efficient, and the method has good operation convenience and industrial application potential.

Description

Technical Field

[0001] This invention relates to a method for preparing cyclobutene framework compounds by visible light photocatalysis. Background Technology

[0002] Cyclobutenes are a representative class of small-ring organic compounds, containing a highly strained four-membered carbon ring and a carbon-carbon double bond. Due to the ring strain and the binding effect of the double bond's π electrons, they exhibit high reactivity under thermal, light, or catalytic conditions. The high ring strain of these molecules mainly stems from the angular strain of the four-membered ring and the restricted electron density distribution of the double bond, making them prone to structural rearrangements and chemical transformations, such as ring-opening, ring-expansion, and [2+2] or [4+2] cycloaddition reactions. Therefore, cyclobutenes have important intermediate value in organic synthesis.

[0003] Further transformation of the cyclobutene skeleton allows for the efficient construction of various complex carbon skeleton structures, including linear carbon chains, monocyclic and polycyclic fused systems, particularly suitable for constructing multi-bridged carbon rings and stereocomplex skeletons commonly found in natural product synthesis. Furthermore, the high reactivity and structural diversity of cyclobutene provide important tools for the structural modification of drug molecules and the development of precursors for functional materials. Therefore, developing an efficient, mild, and highly selective strategy for constructing cyclobutene is of great significance for promoting the development of green synthetic chemistry and improving the efficiency of target molecule synthesis.

[0004] Currently, the main methods for synthesizing cyclobutene compounds include the following categories: First, using alkenes and alkynes as reaction substrates, cyclobutene structures are constructed through intermolecular [2+2] cycloaddition. This method is relatively simple, but it typically relies on high-intensity ultraviolet light sources or noble metal catalytic systems, resulting in harsh reaction conditions, poor substrate adaptability, and difficulty in selective control, which hinders practical applications and industrial scale-up. Second, cyclobutene is formed by dehydrogenation or removal of leaving groups from cyclobutane precursors, or by inducing rearrangement of small-ring precursors such as cyclopropene, cyclopentadiene, and bicyclo[1.1.0]butane under thermal or photothermal conditions. However, this strategy often requires multiple reaction steps to construct the precursor, resulting in low overall efficiency.

[0005] Despite the high value of cyclobutene synthesis, existing methods still have significant limitations in terms of catalytic efficiency, substrate versatility, functional group compatibility, and environmental sustainability. Therefore, developing a simple, mild, and widely applicable method for cyclobutene synthesis remains of significant research importance and application potential. In recent years, the development of visible light photocatalysis has provided new avenues for cyclobutene synthesis. Compared to traditional ultraviolet light sources, visible light has the advantages of longer wavelengths and lower energy, enabling selective excitation reactions under low energy consumption conditions, effectively avoiding the decomposition of thermosensitive substrates and suppressing side reactions. Furthermore, visible light photocatalysis typically uses inexpensive small organic molecules or metal complexes as photocatalysts, resulting in environmentally friendly reaction conditions with good scalability and industrial application potential. Therefore, developing new strategies for cyclobutene synthesis based on visible light photocatalysis is one of the important research directions in the field of organic synthesis. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a method for preparing cyclobutene skeleton compounds using visible light photocatalysis. This method involves converting conjugated diene compounds into cyclobutene skeleton compounds under visible light catalysis and inert gas protection. The intramolecular electrocyclization method for conjugated diene substrates provided by this invention, based on an energy transfer mechanism, overcomes the shortcomings of existing methods, such as harsh intermolecular reaction conditions and poor selectivity. Under visible light irradiation, this method utilizes a photocatalyst to excite the substrate, achieving direct conversion of raw materials into cyclobutene target products without the need for additional oxidants or reductants. The reaction process exhibits high atom economy, theoretically reaching 100% atom utilization. Furthermore, the reaction conditions are mild, the substrate range is wide, and it demonstrates good functional group compatibility and selectivity control, showing promising practical application prospects and industrial promotion potential.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0008] This invention provides a method for preparing a cyclobutene compound, comprising the following steps:

[0009] In a solvent, in the presence of a photocatalyst, and under visible light irradiation, conjugated diene compound I undergoes a cyclization reaction to yield cyclobutene compound II;

[0010] The first carbon-carbon double bond in the conjugated diene of the conjugated diene compound I is located in a six-membered non-aromatic ring, and the second carbon-carbon double bond is not on the same ring as the first carbon-carbon double bond.

[0011] The cyclobutene compound II contains a six-membered non-aromatic ring-p-cyclobutene structure; in the six-membered non-aromatic ring-p-cyclobutene structure, the non-aromatic six-membered ring and the cyclobutene share two carbon atoms to form a fused ring; and among the shared carbon atoms, only one is an unsaturated carbon in a carbon-carbon double bond.

[0012] In the conjugated diene compound I and cyclobutene compound II, the six-membered non-aromatic ring is a carbocyclic ring or a carbon heterocyclic ring; in the carbon heterocyclic ring, the number of heteroatoms or heterogroups is 1, 2, or 3, and the heteroatoms or heterogroups are independently -O-, -S-, -NH-, or -N(R) x One or more of - and -S(=O)2-; R x It is an amino protecting group;

[0013] In the conjugated diene compound I and cyclobutene compound II, the six-membered non-aromatic ring may or may not have substituents.

[0014] In certain preferred embodiments of the present invention, certain conditions, operations, or materials in the preparation method of the cyclobutene compound have the following definitions, and conditions, operations, or materials not mentioned are the same as those described in any embodiment of the present invention (hereinafter referred to as "in a certain embodiment"). Other aspects of the present invention are referred to using the same abbreviations as this invention and will not be described in detail hereafter.

[0015] In one embodiment, the first carbon-carbon double bond and the second carbon-carbon double bond are conjugated.

[0016] In one embodiment, during the ring-closing reaction, in the conjugated diene compound I, the first carbon-carbon double bond and the second carbon-carbon double bond are broken; after the breakage, an unsaturated carbon in the first carbon-carbon double bond and an unsaturated carbon in the second carbon-carbon double bond are directly connected to form a carbon-carbon double bond in the cyclobutene structure of the cyclobutene compound II.

[0017] In one embodiment, only the first carbon-carbon double bond and the second carbon-carbon double bond in the conjugated diene compound I participate in the ring-closing reaction.

[0018] In one embodiment, the second carbon-carbon double bond is an intracyclic double bond of another six-membered non-aromatic ring, or the second carbon-carbon double bond is a non-intracyclic double bond.

[0019] In one embodiment, the second carbon-carbon double bond in the conjugated diene compound I is not located within any ring.

[0020] In one embodiment, the second carbon-carbon double bond in the conjugated diene compound I is located on another six-membered non-aromatic ring.

[0021] In one embodiment, the solvent is one or more of the following: haloalkanes, ethers, nitriles, ketones, alcohols, alkanes, sulfoxides, esters, amides, and aromatics.

[0022] The halogenated hydrocarbon solvent is preferably C444 substituted with one or more halogens. 1-6 Alkanes, more preferably C4 substituted with one or more chlorine atoms. 1-6 Alkanes, such as dichloromethane;

[0023] The ether solvent is preferably a cyclic ether solvent, such as tetrahydrofuran;

[0024] The preferred nitrile solvent is acetonitrile;

[0025] The preferred ketone solvent is acetone;

[0026] The preferred alcohol solvent is C. 1-6 Alcohol solvents, such as methanol;

[0027] The preferred alkane solvent is C. 1-10 Alkane solvents, such as n-hexane;

[0028] The sulfoxide solvent is preferably dimethyl sulfoxide;

[0029] The preferred ester solvent is ethyl acetate;

[0030] The preferred amide solvent is N,N-dimethylacetamide;

[0031] The aromatic hydrocarbon solvent is preferably toluene.

[0032] In one embodiment, the solvent is a halogenated hydrocarbon solvent or an ether solvent, such as dichloromethane and tetrahydrofuran.

[0033] In one embodiment, the ratio of the amount of the conjugated diene compound I to the volume of the solvent is within the conventional range in the art, as long as it does not affect the cyclization reaction.

[0034] In one embodiment, the ratio of the amount of the conjugated diene compound I to the volume of the solvent is 0.01-1.0 mol / L, preferably 0.01-0.1 mol / L, for example 0.05 mol / L.

[0035] In one embodiment, the photocatalyst is a complex of metallic iridium or an organic photocatalyst;

[0036] The organic photocatalyst is preferably photocatalyst 3 or a tricyclic organic photocatalyst; the tricyclic organic photocatalyst is preferably photocatalyst 6, 7 or 8.

[0037]

[0038] In one embodiment, the photocatalyst is a photocatalyst with a triplet energy > 55 kcal / mol; the photocatalyst with a triplet energy > 55 kcal / mol is preferably a metal iridium complex with a triplet energy > 55 kcal / mol or an organic photocatalyst with a triplet energy > 55 kcal / mol; the organic photocatalyst is a photocatalyst that can catalyze photoreactions and does not contain metal ions.

[0039] In one embodiment, the iridium complex with triplet energy >55 kcal / mol is photocatalyst 1, 2, 4, or 5;

[0040]

[0041] In one embodiment, the organic photocatalyst with a triplet energy >55 kcal / mol is photocatalyst 3 or a tricyclic organic photocatalyst; the tricyclic organic photocatalyst is preferably photocatalyst 6, 7 or 8;

[0042]

[0043] In one embodiment, the organic photocatalyst with a triplet energy >55 kcal / mol is a tricyclic organic photocatalyst; the tricyclic organic photocatalyst contains two aromatic rings and one non-aromatic carbon heterocycle.

[0044] Preferably, the tricyclic organic photocatalyst has an aromatic ring-non-aromatic carbon heterocycle-aromatic ring framework structure;

[0045] Preferably, the aromatic ring is C 6-12 Aromatic rings, such as benzene rings;

[0046] Preferably, the aromatic ring is optionally substituted with a substituent, which is preferably a halogen or alkyl group;

[0047] Preferably, the heteroatom in the non-aromatic carbon heterocycle is O or S;

[0048] Preferably, the non-aromatic carbon heterocycle is a non-aromatic carbon heterocycle substituted with a carbonyl group;

[0049] More preferably, the non-aromatic carbon heterocycle is

[0050] In one embodiment, the tricyclic organic photocatalyst is...

[0051] In one embodiment, the photocatalyst is one or more of the following photocatalysts:

[0052]

[0053] In one embodiment, the ratio of the amount of the photocatalyst to the amount of the conjugated diene compound I is within the conventional range in the art, as long as it does not affect the cyclization reaction.

[0054] In one embodiment, the molar ratio of the photocatalyst to the conjugated diene compound I is (0.005-0.05):1, for example, 0.02:1.

[0055] In one embodiment, the ratio of the amount of the photocatalyst to the volume of the solvent is 0.0002-0.02 mol / L, preferably 0.0002-0.002 mol / L, for example 0.001 mol / L.

[0056] In one embodiment, the wavelength of the visible light is 410nm±60nm; preferably, the wavelength of the visible light is 455nm±15nm (e.g., 455-460nm) or 375±20nm (e.g., 385-390nm).

[0057] In one embodiment, when the photocatalyst is a complex of metallic iridium with a triplet energy >55 kcal / mol, the wavelength of the visible light is 455 nm ± 15 nm, for example, 455-460 nm.

[0058] Preferably, the iridium complex with triplet energy >55 kcal / mol is one or more of photocatalysts 1, 2, 4 and 5;

[0059]

[0060] In one embodiment, when the photocatalyst is a tricyclic organic photocatalyst with a triplet energy >55 kcal / mol, the wavelength of the visible light is 375 ± 20 nm, for example, 385-390 nm.

[0061] Preferably, the tricyclic organic photocatalyst with a triplet energy >55 kcal / mol is one or more of photocatalysts 6-8;

[0062]

[0063] In one embodiment, when the organic photocatalyst with a triplet energy > 55 kcal / mol is photocatalyst 3,

[0064]

[0065] The wavelength of the visible light is 455nm ± 15nm, for example, 455-460nm.

[0066] In one embodiment, the power of the visible light source is within the conventional range in the art, as long as it does not affect the cyclization reaction. The power of the light source is used according to the reaction scale. For example, when the reaction system is less than 10 mL, a light source with a power of 6 W can be used; for example, when the reaction system is more than 150 mL, a light source with a power of 40-80 W can be used.

[0067] In one embodiment, the power of the visible light source is 1-100 watts, for example, 6 watts.

[0068] In one embodiment, the visible light source is a 6-watt blue LED lamp with a wavelength of 455-460nm.

[0069] In one embodiment, the cyclization reaction is an intramolecular reaction occurring in the conjugated diene compound I.

[0070] In one embodiment, the progress of the cyclization reaction is monitored using conventional detection methods in the art (e.g., HPLC), and the reaction endpoint is generally defined as the disappearance or cessation of reaction of one of the reactants in the reaction solution. The preferred reaction time for the cyclization reaction is 20-60 hours, for example, 36 hours.

[0071] In one embodiment, the temperature of the cyclization reaction is a conventional temperature in the art, as long as it does not affect the progress of the cyclization reaction.

[0072] In one embodiment, the cyclization reaction is carried out at a temperature of 10-40°C, preferably 20-30°C, for example 25°C.

[0073] In one embodiment, the cyclization reaction is carried out under the protection of an inert gas.

[0074] The inert gas is preferably argon (Ar) and / or nitrogen (N2).

[0075] In one embodiment, the cyclization reaction is carried out at atmospheric pressure.

[0076] In one embodiment, the cyclization reaction uses only the materials mentioned in the technical solutions described in the specification, and does not involve other materials.

[0077] In one aspect of the present invention, R x It is a sulfonyl amino protecting group, an acyl amino protecting group, or a carbonate amino protecting group;

[0078] The sulfonyl amino protecting group is preferably Ms (methanesulfonyl), Tf (trifluoromethanesulfonyl), Ts (p-methylbenzenesulfonyl), benzenesulfonyl, p-fluorobenzenesulfonyl, or Bs (p-bromobenzenesulfonyl);

[0079] The acyl amino protecting group is preferably Bz (benzoyl), Ac (acetyl), Tfa (trifluoroacetyl) or Piv (pivaloyl);

[0080] The preferred amino protecting group of the carbonate is Fmoc (9-fluorenylmethylcarbonyl), Troc (2,2,2-trichloroethoxycarbonyl), Boc (tert-butyloxycarbonyl), Cbz (benzyloxycarbonyl) or Alloc (allyloxycarbonyl).

[0081] In one particular scheme, R x It can be Ts (p-toluenesulfonyl), Boc (tert-butoxycarbonyl), Ac (acetyl), Bz (benzoyl), Cbz (benzyloxycarbonyl), Bs (p-bromobenzenesulfonyl) or Ms (methanesulfonyl), preferably Ts or Boc.

[0082] In one embodiment, the six-membered non-aromatic ring in the conjugated diene compound I is...

[0083] In one embodiment, the "six-membered non-aromatic ring--cyclobutene structure" in the cyclobutene compound II is...

[0084] In one embodiment, when the six-membered non-aromatic ring is a carbon heterocycle in the conjugated diene compound I and cyclobutene compound II, the number of heteroatoms or heteroatomic groups is 1.

[0085] In one embodiment, the structure of the conjugated diene compound I is shown in formula I-1 or formula I-2:

[0086]

[0087] Among them, R 1 for -O-, -S-, -S(=O)2- or -N(R) 1c )-;

[0088] R 1a and R 1b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH, -OC 1-6 Alkyl or halogen;

[0089] R 1c Amino protecting group, H, C1-6 Alkyl or C 6-14 Aryl;

[0090] n is any integer greater than or equal to 0;

[0091] R 2 H, halogen, C 1-6 Alkyl, C 6-14 Aryl, C 3-12 cycloalkyl, -OR 2c -OC(=O)-R 2d -C(=O)-R 2e -C(R) 2f R 2g R 2h -SC(=O)-C 1-6 Alkyl, -OS(=O)-C 6-14 Aryl, -SO2-C 6-14 aryl, 5-12 heteroaryl, 5-12 heteroaryl substituted with one or more carbonyl groups, or C substituted with one or more halogens. 1-6 alkyl;

[0092] R 2a and R 2b Independently protected by amino, H, C 1-6 Alkyl, C 6-14 Aryl, OH, -OC 1-6 Alkyl or -C(=O)-R 2aa ;

[0093] R 2aa C 1-6 Alkyl groups or C atoms substituted with one or more halogens 1-6 alkyl;

[0094] R 2c For H, C 1-6 Alkyl, C 6-14 Aryl, hydroxyl protecting group, C 2-8 alkenyl or C 2-8 alkynyl group;

[0095] R 2d For H, C 1-6 Alkyl, C 6-14 Aryl, C 3-12 cycloalkyl, C 2-8 alkenyl, C 2-8 alkynyl group, -C 1-6 Alkylene-R 2da , C replaced by one or more halogens 1-6 Alkyl groups or C groups substituted with one or more carbonyl groups 3-12Cycloalkyl;

[0096] R 2da CN, -C (=O) -C 1-6 alkyl, by one or more R 2daa Replacement C 6-14 aryl or aryl with one or more R 2dab Replacement C 3-12 Cycloalkyl;

[0097] R 2daa Independently for -OC 1-6 Alkyl or C 1-6 alkyl;

[0098] R 2dab Independently for C 1-6 Alkyl, OH or -OC 1-6 alkyl;

[0099] R 2e For H, OH, C 1-6 Alkyl or -OC 1-6 alkyl;

[0100] R 2f R 2g and R 2h Independently for C 1-6 Alkyl or -COO-C 1-6 alkyl;

[0101] R 3 for -O-, -S-, -S(=O)2- or -N(R) 3c )-;

[0102] R 3a and R 3b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl;

[0103] R 3c It is an amino protecting group;

[0104] R 4 for -O-, -S-, -S(=O)2- or -N(R) 4c )-;

[0105] R 4a and R 4b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6alkyl;

[0106] R 4c It is an amino protecting group.

[0107] In one particular scheme, R 1a and R 1b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl.

[0108] In one particular scheme, R 1a For H.

[0109] In one particular scheme, R 1b For H, C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl.

[0110] In one particular scheme, R 1b It can be H, methyl, ethyl, tert-butyl, phenyl, OH, or -O-CH3.

[0111] In one particular scheme, R 1 In the middle, the said for

[0112] In one particular scheme, R 1c It is an amino protecting group.

[0113] In one particular scheme, R 1c R 2a R 2b R 3c and R 4c In this context, the amino protecting group is preferably a sulfonyl amino protecting group, an acyl amino protecting group, or a carbonate amino protecting group;

[0114] The sulfonyl amino protecting group is preferably Ms (methanesulfonyl), Tf (trifluoromethanesulfonyl), Ts (p-methylbenzenesulfonyl), benzenesulfonyl, p-fluorobenzenesulfonyl, or Bs (p-bromobenzenesulfonyl);

[0115] The acyl amino protecting group is preferably Bz (benzoyl), Ac (acetyl), Tfa (trifluoroacetyl) or Piv (pivaloyl);

[0116] The preferred amino protecting group of the carbonate is Fmoc (9-fluorenylmethylcarbonyl), Troc (2,2,2-trichloroethoxycarbonyl), Boc (tert-butyloxycarbonyl), Cbz (benzyloxycarbonyl) or Alloc (allyloxycarbonyl).

[0117] In one particular scheme, R 1c It can be Ts (p-toluenesulfonyl), Boc (tert-butyloxycarbonyl), Ac (acetyl), Bz (benzoyl), Cbz (benzyloxycarbonyl), Bs (p-bromobenzenesulfonyl) or Ms (methanesulfonyl).

[0118]

[0119] In one scheme, the -N(R) 1c )-for

[0120]

[0121] In one particular scheme, R 1 It can be any of the following structures:

[0122]

[0123] In a certain scheme, n is any integer ≥ 0 and ≤ 10;

[0124] Preferably, n is any integer ≥0 and ≤5, such as 0, 1, 2, 3, 4 or 5.

[0125] In one particular scheme, R 2 In this context, the 5-12 membered heteroaryl group substituted with one or more carbonyl groups is...

[0126] In one particular scheme, R 2c In this context, the hydroxyl protecting group is a sulfonyl hydroxyl protecting group, an acyl hydroxyl protecting group, a carbonate hydroxyl protecting group, an acetal hydroxyl protecting group, or a silyl ether hydroxyl protecting group;

[0127] The sulfonyl hydroxyl protecting group is preferably Ms (methanesulfonyl), Tf (trifluoromethanesulfonyl), Ts (p-methylbenzenesulfonyl), benzenesulfonyl, p-fluorobenzenesulfonyl, or Bs (p-bromobenzenesulfonyl);

[0128] The acyl hydroxyl protecting group is preferably Bz (benzoyl), Ac (acetyl), Tfa (trifluoroacetyl) or Piv (pivaloyl);

[0129] The carbonate hydroxyl protecting group is preferably Fmoc (9-fluorenylmethylcarbonyl), Troc (2,2,2-trichloroethoxycarbonyl), Boc (tert-butyloxycarbonyl), Cbz (benzyloxycarbonyl) or Alloc (allyloxycarbonyl);

[0130] The acetal hydroxyl protecting group is preferably MOM (methoxymethyl ether) or THP (2-tetrahydropyran);

[0131] The hydroxyl protecting group of the silyl ether is preferably TMS (trimethylsilyl ether), TBDMS (tert-butyl dimethyl silyl ether), or TBDPS (tert-butyl diphenyl silyl ether).

[0132] In one particular scheme, R 2c In this context, the hydroxyl protecting group is Bz or Ts.

[0133] In one particular scheme, R 2d In, the C 1-6 Alkyl groups are -CH2-, -CH2-CH2-, Or -CH2-CH2-CH2-.

[0134] In one particular scheme, R 2 It can be any of the following structures:

[0135]

[0136]

[0137] In one particular scheme, R 3 It can be any of the following structures:

[0138]

[0139] In one particular scheme, R 4 It can be any of the following structures:

[0140]

[0141] In one embodiment, the structure of the cyclobutene compound II is shown in formula II-1 or formula II-2:

[0142]

[0143] Among them, R 1 R 2 n, R 3 and R 4 The definition is as described in the previous scheme.

[0144] In one embodiment, the structure of formula II-2 is shown in formula II-2a:

[0145]

[0146] Among them, R 3 and R 4 The definition is as described in the previous scheme.

[0147] In one embodiment, the conjugated diene compound I and the corresponding cyclobutene compound II have either of the following structures:

[0148]

[0149]

[0150]

[0151]

[0152] Unless otherwise specified, the terms used in this invention may be defined as follows:

[0153] Those skilled in the art will understand that, according to conventions used in the art, the structural formulas of the groups described in this invention are... This refers to the fact that the corresponding group is connected to other fragments or groups in the compound through this site.

[0154] In this article, the substituents used may be preceded by a single dash "-" to indicate that the named substituent is connected to the parent moiety by a single bond.

[0155] When one of the variables is selected as a chemical bond, it means that the two groups connected to it are directly linked.

[0156] In the term "one or more," when any variable is "multiple," the meaning of each variable is independent and does not affect the others; for example, "methyl group substituted with one or more halogens" can be -CH2Br, -CHBr2, -CF3, or...

[0157] Terms like "intracyclic double bond" and "the first carbon-carbon double bond is located in a six-membered non-aromatic ring" refer to the fact that the two terminal atoms of a carbon-carbon double bond are on the same ring, which are the two vertices of the same ring.

[0158] The term "multiple" refers to 2, 3, 4, 5, or 6.

[0159] The term "halogen" refers to F, Cl, Br, or I.

[0160] The term "alkyl" refers to a straight-chain or branched alkyl group having a specified number of carbon atoms (e.g., C1-C6). Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, etc.

[0161] The term "alkylene" refers to a straight-chain divalent hydrocarbon group or a branched divalent hydrocarbon group having a specified number of carbon atoms (e.g., C1-C6). Examples of alkylene groups include, but are not limited to, methylene, ethylene, propylene, 1-methylpropylene, butylene, etc.

[0162] The term "alkenyl" refers to a group having a specific number of carbon atoms (e.g., C10, C20, C30, C40, C50, C60, C70, C80, C9 ... 2-4A straight-chain or branched hydrocarbon group with one or more double bonds. The one or more carbon-carbon double bonds can be internal or terminal.

[0163] The term "alkynyl" refers to a group having a specific number of carbon atoms (e.g., C10, C20, C30, C40, C50, C60, C70, C80, C9 ... 2-4 A straight-chain or branched hydrocarbon group with one or more triple bonds. The one or more carbon-carbon triple bonds can be internal or terminal.

[0164] The term "cycloalkyl" refers to a ring with a specified number of carbon atoms (e.g., C15, C25, C35, C45, C5 ... 3-8 Cycloalkyl groups are saturated cyclic groups whose ring atoms consist only of carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0165] The term "aromatic ring" refers to a ring having a specified number of carbon atoms (e.g., C6-C). 14 Aromatic rings are aromatic cyclic structures that are monocyclic or polycyclic (e.g., two or three rings). Aromatic rings include, but are not limited to, benzene rings, naphthalene rings, etc.; the term "aryl" refers to a structure obtained by losing one hydrogen atom based on the definition of the term "aromatic ring".

[0166] The term "heteroaryl" refers to a cyclic, unsaturated monovalent group having a specified number of ring atoms (e.g., 5-12), a specified number of heteroatoms (e.g., 1, 2, or 3), and a specified type of heteroatom (one or more of N, O, and S), which can be monocyclic or polycyclic; if polycyclic, the monocyclic rings share two atoms and one bond, and at least one ring is aromatic. Heteroaryl groups are attached to the rest of the molecule via carbon atoms or heteroatoms; they are attached to the rest of the molecule via rings with or without heteroatoms; they are attached to the rest of the molecule via aromatic or non-aromatic rings. Heteroaryl groups include, but are not limited to: wait.

[0167] The term "carbocyclic ring" refers to a saturated cyclic group having a specified number of carbon atoms (e.g., C3-C6) and whose ring atoms consist solely of carbon atoms. Examples of carbocyclic rings include, but are not limited to, those mentioned above. wait.

[0168] The term "carbon heterocycle" refers to a ring with a specified number of ring atoms (e.g., 3-8), a specified number of heteroatoms or heterogroups (e.g., 1, 2, or 3), and a specified type of heteroatom or heterogroup (-O-, -S-, -NH-, -N(R)). x Saturated cyclic groups of one, two, or three of the following: - and -S(=O)2-. Examples of carbon heterocycles include, but are not limited to, oxetane propane, azirane propane, oxetane butane, azirane butane, tetrahydropyrrole, tetrahydrofuranyl, tetrahydropyranyl, piperidinyl, morpholinyl, or piperazine.

[0169] The term "cycloalkene" refers to an unsaturated cyclic group having a specified number of ring carbon atoms (e.g., C3-C8), with the ring atoms consisting only of saturated and unsaturated carbon atoms, and containing a partially unsaturated alkenyl group; the cycloalkenyl group is non-aromatic and does not contain any aromatic rings.

[0170] The term "cycloalkyl" refers to a ring with a specified number of carbon atoms (e.g., C15, C25, C35, C45, C5 ... 3-8 Cycloalkyl groups are saturated cyclic groups whose ring atoms consist only of carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0171] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0172] The reagents and raw materials used in this invention are all commercially available.

[0173] The positive and progressive effects of this invention are as follows: The beneficial effects of this invention include, but are not limited to, the following:

[0174] 1. Mild conditions and environmentally friendly: The reaction is carried out under visible light irradiation, without the need for high temperature, high pressure or strong oxidizing and reducing agents, avoiding energy waste and side reactions, which is in line with the development concept of green chemistry.

[0175] 2. High atom economy: This reaction does not require the addition of sacrificial reagents or the introduction of additional functional groups. All atoms are effectively converted into the target product, and the theoretical atom utilization rate can reach 100%, which has excellent atom economy.

[0176] 3. High selectivity and wide substrate applicability: This method is based on the intramolecular electrocyclization pathway, which has excellent regioselectivity and configuration control capabilities. It is applicable to a variety of conjugated diene substrates, compatible with a variety of functional group structures, and has good substrate versatility.

[0177] 4. The catalytic system is inexpensive and readily available: the photocatalysts used are abundant and readily available, the reaction system is stable, and it does not rely on precious metal catalysts or special reagents, thus having good cost control capabilities and scalability potential.

[0178] 5. Simple operation and strong applicability: The entire reaction process does not require strict anhydrous and oxygen-free operation. The conversion can be completed simply by stirring and irradiation under inert gas protection. The operation is simple and easy to scale up, and it is suitable for organic synthesis and related industrial applications. Detailed Implementation

[0179] The present invention is further illustrated below by way of examples, but these examples do not limit the invention to the scope of the embodiments described. Experimental methods not specifically described in the following examples were performed according to conventional methods and conditions, or as selected according to the product instructions. All reagents used in this application are commercially available and can be used without further purification.

[0180] In the following embodiments, unless otherwise specified, the structures of photocatalysts 1 to 8 are as follows:

[0181]

[0182] The relevant information for blue LED light sources is as follows:

[0183]

[0184] Example 1:

[0185]

[0186] Under an argon atmosphere, conjugated diene compound I-1 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and DCM (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using n-pentane as the eluent. The starting material conversion was 100%, and product II-1 was a colorless oil with a yield of 71%. 1 H NMR(400MHz, CD2Cl2)δ2.46(dt,J=12.4,4.4Hz,1H),2.30–2.19(m,2H),2.00–1.94(m,1H),1.91–1. 85(m,1H),1.81–1.74(m,2H),1.71–1.66(m,1H),1.60(s,3H),1.28–1.16(m,2H),1.05–0.96(m,1H); 13 C NMR (101MHz, CD2Cl2) δ144.6,130.2,38.6,38.3,33.7,27.3,25.7,25.4,13.9.

[0187] Preparation of conjugated diene compound I-1:

[0188]

[0189] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-1 in 47% yield. 1 H NMR (400MHz, CD2Cl2) δ5.90(s,1H),4.95(s,1H),4.82(s,1H),2.22–2.12(m,4H),1.89(s,3H),1.71–1.65(m,2H),1.61–1.56(m,2H); 13 C NMR (101MHz, CD2Cl2) δ144.3,136.9,125.3,109.6,26.3,25.9,23.4,22.7,20.8.

[0190] Example 2:

[0191]

[0192] Under an argon atmosphere, conjugated diene compound I-2 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and DCM (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using n-pentane as the eluent. The starting material conversion was 100%, and product II-2 was a colorless oil with a yield of 79%. 1 H NMR(400MHz, CD2Cl2)δ2.45(dt,J=12.3,3.7Hz,1H),2.36–2.30(m,1H),2.23–2.15(m,1H),2.04–1.96( m,3H),1.90–1.85(m,1H),1.84–1.75(m,2H),1.72–1.67(m,1H),1.28–1.17(m,2H),1.05–0.97(m,4H); 13C NMR (101MHz, CD2Cl2) δ143.3,136.1,37.8,36.4,33.9,27.5,25.84,25.76,22.6,12.6.

[0193] Preparation of conjugated diene compound I-2:

[0194]

[0195] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-2 in 64% yield. 1 H NMR(400MHz,CD2Cl2)δ5.93(s,1H),4.97(s,1H),4.83(s,1H),2.29(q,J=7.4Hz,2H ),2.22–2.14(m,4H),1.74–1.67(m,2H),1.64–1.57(m,2H),1.09(t,J=7.4Hz,3H); 13 CNMR(101MHz,CD2Cl2)δ150.8,136.4,124.4,107.7,26.8,26.6,26.4,23.6,22.9,13.9.

[0196] Example 3:

[0197]

[0198] Under an argon atmosphere, conjugated diene compound I-3 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and DCM (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using n-pentane as the eluent. The starting material conversion was 100%, and product II-3 was a colorless oil with a yield of 70%. 1H NMR(400MHz, CD2Cl2)δ2.40–2.34(m,1H),2.25(dt,J=12.2,3.6Hz,1H),2.18–2.08(m,1H),1.99–1.93(m,1H),1.86–1.75( m,2H),1.72–1.66(m,2H),1.45–1.34(m,1H),1.28–1.17(m,2H),1.03–0.93(m,1H),0.63–0.51(m,2H),0.48–0.34(m,2H); 13 C NMR (101MHz, CD2Cl2) δ142.8,135.2,36.7,33.7,33.6,27.3,25.6,9.9,4.8,4.5.

[0199] Preparation of conjugated diene compound I-3:

[0200]

[0201] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to ensure inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-3 in 48% yield. 1 H NMR(400MHz,CD2Cl2)δ6.29(s,1H),4.91(s,1H),4.73(s,1H),2.21–2.16(m,4H),1.72–1 .67(m,2H),1.63–1.58(m,2H),1.49–1.42(m,1H),0.71–0.66(m,2H),0.43–0.39(m,2H); 13 C NMR (101MHz, CD2Cl2) δ150.0,136.9,125.4,106.6,26.6,26.3,23.5,22.8,14.5,6.1.

[0202] Example 4:

[0203]

[0204] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The starting material conversion was 100%, and product II-4 was a colorless oil with a yield of 78%. When photocatalyst 3 was used instead of photocatalyst 2, the yield was 72% after 36 hours of irradiation with a 6-watt blue LED lamp (455-460 nm). When photocatalyst 4 was used instead of photocatalyst 2, the yield was 42% after 36 hours of irradiation with a 6-watt blue LED lamp (455-460 nm). When photocatalyst 5 was used instead of photocatalyst 2 in the reaction, and irradiated with a 6-watt blue LED lamp at 455-460 nm, the reaction time was 36 hours, and the yield was 66%. When photocatalyst 6 was used instead of photocatalyst 2 in the reaction, and irradiated with a 6-watt LED lamp at 385-390 nm, the reaction time was 36 hours, and the yield was 35%. When photocatalyst 7 was used instead of photocatalyst 2 in the reaction, and irradiated with a 6-watt LED lamp at 385-390 nm, the reaction time was 36 hours, and the yield was 41%. When photocatalyst 8 was used instead of photocatalyst 2 in the reaction, and irradiated with a 6-watt LED lamp at 385-390 nm, the reaction time was 36 hours, and the yield was 45%.

[0205] 1 H NMR (400MHz, CDCl3) δ7.67(d,J=8.2Hz,2H),7.31(d,J=8.2Hz,2H),3.63–3.47(m,2H),2.68(s,3H),2.43(s,3H),2.43–2.38(m,1H),2 .31–2.19(m,2H),2.05–1.98(m,1H),1.91–1.86(m,1H),1.84–1.74(m,2H),1.72–1.67(m,1H),1.26–1.08(m,2H),1.03–0.92(m,1H); 13 C NMR (101MHz, CDCl3) δ150.8,143.1,134.4,129.5,127.5,127.2,47.4,38.0,36.1,34.3,33.2,26.9,25.1,24.9,21.5.

[0206] Preparation of conjugated diene compound I-4:

[0207]

[0208] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-4 in 52% yield. 1 H NMR (400MHz, CDCl3) δ7.68(d,J=8.2Hz,2H),7.34(d,J=8.2Hz,2H),6.12(s,1H),5.13(s,1H),4.92(s, 1H),3.74(s,2H),2.57(s,3H),2.44(s,3H),2.19–2.12(m,4H),1.70–1.64(m,2H),1.60–1.53(m,2H); 13 C NMR (101MHz, CDCl3) δ143.3,142.1,133.7,129.6,127.5,126.6,112.9,53.4,34.1,25.9,25.8,22.7,22.0,21.5.

[0209] Example 5:

[0210]

[0211] Under an argon atmosphere, conjugated diene compound I-5 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (4:1) as the eluent. The conversion rate of the starting material was 100%, and product II-5 was a colorless oil with a yield of 90%. 1HNMR(400MHz, CDCl3)δ4.07(s,2H),2.57(dt,J=12.4,3.7Hz,1H),2.42–2.34(m,1H),2.32–2.22(m, 1H),2.07–1.97(m,2H),1.90–1.79(m,3H),1.75–1.67(m,1H),1.32–1.16(m,2H),1.10–0.99(m,1H); 13 C NMR (101MHz, CDCl3) δ147.5,132.2,59.2,37.8,35.0,33.0,26.8,25.4,24.9.

[0212] Preparation of conjugated diene compound I-5:

[0213]

[0214] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to ensure inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-5 in 55% yield. 1 H NMR (400MHz, CDCl3) δ5.95(s,1H),5.10(s,2H),4.34(s,2H),2.21–2.14(m,4H),1.73–1.67(m,2H),1.62–1.57(m,2H),1.50(br,1H); 13 C NMR (101MHz, CDCl3) δ147.3,134.1,125.1,109.8,64.4,25.84,25.75,22.7,22.1.

[0215] Example 6:

[0216]

[0217] Under an argon atmosphere, conjugated diene compound I-6 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The starting material conversion was 100%, and product II-6 was a colorless oil with a yield of 82%. When photocatalyst 3 was used instead of photocatalyst 2, the yield was 80%. 1 H NMR(400MHz, CDCl3) δ3.68(t,J=6.4Hz,2H),2.55–2.49(m,1H),2.35–2.22(m,4H),2.06–1.99(m,1 H),1.97–1.91(m,1H),1.87–1.79(m,2H),1.74–1.67(m,1H),1.29–1.13(m,2H),1.06–0.95(m,1H); 13 C NMR (101MHz, CDCl3) δ147.7,130.0,60.8,37.9,36.5,33.5,32.2,27.1,25.4,25.0.

[0218] Preparation of conjugated diene compound I-6:

[0219]

[0220] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-6 in 91% yield. 1H NMR (400MHz, CDCl3) δ5.91(s,1H),5.07(s,1H),4.87(s,1H),3.68(t,J=6.6Hz,2H ),2.53(t,J=6.6Hz,2H),2.22–2.10(m,5H),1.72–1.62(m,2H),1.62–1.52(m,2H); 13 C NMR (101MHz, CDCl3) δ144.5,135.2,124.9,110.7,61.5,36.7,25.8,25.7,22.7,22.0.

[0221] Example 7:

[0222]

[0223] Under an argon atmosphere, conjugated diene compound I-7 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-7 was a yellow oily substance with a yield of 66%. 1 H NMR (400MHz, CDCl3) δ3.65(t,J=6.6Hz,2H),2.46(dt,J=12.5,3.7Hz,1H),2.32–2.26(m,1H),2.25–2.17(m,1H),2.07(t,J=7 .5Hz,2H),2.02–1.96(m,1H),1.91–1.87(m,1H),1.82–1.74(m,3H),1.72–1.65(m,3H),1.27–1.13(m,2H),1.03–0.94(m,1H); 13 C NMR (101MHz, CDCl3) δ144.5,133.3,62.8,37.5,36.4,33.3,30.5,26.9,25.3,25.1,24.9.

[0224] Preparation of conjugated diene compound I-7:

[0225]

[0226] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-7 in 61% yield. 1 H NMR (400MHz, CDCl3) δ5.90 (s, 1H), 4.97 (s, 1H), 4.82 (s, 1H), 3.62 (t, J = 6.5Hz, 2H), 2.5 7(br,1H),2.35–2.29(m,2H),2.19–2.11(m,4H),1.75–1.64(m,4H),1.59–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ147.9,135.4,124.3,108.7,62.4,31.7,29.8,25.9,25.7,22.8,22.0.

[0227] Example 8:

[0228]

[0229] Under an argon atmosphere, conjugated diene compound I-8 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (4:1) as the eluent. The conversion rate of the starting material was 100%, and product II-8 was a colorless oil with a yield of 78%. 1HNMR (400MHz, CDCl3) δ7.79(d,J=8.2Hz,2H),7.34(d,J=8.2Hz,2H),4.08(t,J=6.9Hz,2H),2.45(s,3H),2.41–2.31(m, 3H),2.25–2.12(m,2H),2.00–1.93(m,1H),1.84–1.71(m,3H),1.69–1.63(m,1H),1.27–1.08(m,2H),1.00–0.89(m,1H); 13 C NMR (101MHz, CDCl3) δ147.7,144.6,133.2,129.7,127.8,127.7,68.7,37.9,36.4,33.1,28.4,26.8,25.3,24.9,21.6.

[0230] Preparation of conjugated diene compound I-8:

[0231]

[0232] Compound I-6 (3.0 mmol, 1.0 equiv), TsCl (4.5 mmol, 1.5 equiv), and DMAP (0.3 mmol, 0.1 equiv) were dissolved in 50 mL of anhydrous dichloromethane. Triethylamine (6.0 mmol, 2.0 equiv) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for two hours. After the reaction was complete, the solvent was removed under reduced pressure, and the residue was purified by silica gel column chromatography to give the target product I-8 in 88% yield. 1 H NMR (400MHz, CDCl3) δ7.78(d,J=8.2Hz,2H),7.34(d,J=8.2Hz,2H),5.72(s,1H),5.01(s,1H),4.80(s,1H),4.10 (t,J=7.3Hz,2H),2.60(d,J=7.3Hz,2H),2.45(s,3H),2.11–2.01(m,4H),1.65–1.59(m,2H),1.57–1.49(m,2H); 13 C NMR (101MHz, CDCl3) δ144.6,142.5,134.8,133.2,129.7,127.9,124.9,111.8,69.6,33.1,25.7,22.7,21.9,21.6.

[0233] Example 9:

[0234]

[0235] Under an argon atmosphere, conjugated diene compound I-9 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:diethyl ether at a ratio of 20:1 as the eluent. The conversion rate of the starting material was 100%, and product II-9 was a colorless oil with a yield of 64%. 1 HNMR(400MHz, CD2Cl2)δ3.33(t,J=6.8Hz,2H),3.21(s,3H),2.41–2.36(m,1H),2.22–2.10(m,4H),1.91–1. 87(m,1H),1.82–1.77(m,1H),1.75–1.66(m,2H),1.63–1.57(m,1H),1.19–1.08(m,2H),0.96–0.86(m,1H); 13 C NMR (101MHz, CD2Cl2) δ145.8,131.3,71.4,58.5,38.3,37.1,33.8,29.7,27.4,25.8,25.6.

[0236] Preparation of conjugated diene compound I-9:

[0237]

[0238] I-6 (3.0 mmol, 1.0 equiv), sodium hydride (6.0 mmol, 2.0 equiv), and 15 mL of anhydrous DMF were added to a 100 mL round-bottom flask. The mixture was stirred at 0°C for half an hour, followed by the slow addition of iodomethane (6.0 mmol, 2.0 equiv). The reaction mixture was stirred at 25°C for 8 hours. After the reaction was complete, 100.0 mL of saturated ammonium chloride aqueous solution was added to the mixture, and the mixture was extracted three times with ethyl acetate (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-9 in 92% yield. 1 H NMR (400MHz, CDCl3) δ5.91 (s, 1H), 5.03 (s, 1H), 4.85 (s, 1H), 3.48 (t, J = 7.2Hz, 2H), 3.34 (s,3H),2.55(t,J=7.2Hz,2H),2.20–2.11(m,4H),1.70–1.63(m,2H),1.61–1.54(m,2H); 13C NMR (101MHz, CDCl3) δ144.9,135.5,124.4,110.0,72.3,58.4,33.7,25.83,25.78,22.8,22.1.

[0239] Example 10:

[0240]

[0241] Under an argon atmosphere, conjugated diene compound I-10 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:diethyl ether = 100:1 as the eluent. The conversion rate of the starting material was 100%, and product II-10 was a colorless oil with a yield of 75%. 1 H NMR (400MHz, CD2Cl2) δ7.34–7.22(m,2H),6.98–6.86(m,3H),4.54–4.43(m,2H),2.64–2.57(m,1H),2.44–2.37(m,1H ),2.37–2.27(m,1H),2.08–2.00(m,2H),1.91–1.77(m,2H),1.73–1.67(m,1H),1.32–1.14(m,2H),1.10–1.00(m,1H); 13 C NMR (101MHz, CD2Cl2) δ159.3,149.8,129.7,129.1,120.9,115.1,64.6,38.7,36.0,33.6,27.1,26.0,25.3.

[0242] Preparation of conjugated diene compound I-10:

[0243]

[0244] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to ensure inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-10 in 71% yield. 1 H NMR (400MHz, CD2Cl2) δ7.35–7.27(m,2H),7.02–6.92(m,3H),5.98(s,1H),5.26(s,1H),5.24(s ,1H),4.73(s,2H),2.31–2.24(m,2H),2.23–2.16(m,2H),1.80–1.72(m,2H),1.68–1.61(m,2H); 13 C NMR (101MHz, CD2Cl2) δ159.4,143.8,134.5,129.8,125.9,121.1,115.2,111.7,69.6,26.3,26.2,23.3,22.6.

[0245] Example 11:

[0246]

[0247] Under an argon atmosphere, conjugated diene compound I-11 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:diethyl ether = 40:1 as the eluent. The conversion rate of the starting material was 100%, and the product II-11 was a colorless oil with a yield of 82%. 1HNMR (400MHz, CDCl3) δ8.08–7.98(m,2H),7.57–7.50(m,1H),7.47–7.37(m,2H),4.38(t,J=6.8Hz,2H),2.57–2.40(m,3 H),2.35–2.19(m,2H),2.03–1.94(m,2H),1.84–1.72(m,2H),1.71–1.64(m,1H),1.27–1.10(m,2H),1.05–0.94(m,1H); 13 C NMR (101MHz, CDCl3) δ166.5,146.6,132.7,130.4,129.5,128.2,63.4,37.9,36.7,33.2,28.2,26.8,25.4,25.0.

[0248] Preparation of conjugated diene compound I-11:

[0249]

[0250] Compound I-6 (3.0 mmol, 1.0 equiv) and triethylamine (6.0 mmol, 2.0 equiv) were dissolved in 10 mL of anhydrous dichloromethane. Benzoyl chloride (4.5 mmol, 1.5 equiv) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and stirring for 10 hours. After the reaction was complete, saturated ammonium chloride aqueous solution (50.0 mL) was added to the mixture, and the mixture was extracted three times with ethyl acetate (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-11 in 90% yield. 1 H NMR(400MHz, CDCl3)δ8.04(d,J=6.9Hz,2H),7.58–7.51(m,1H),7.47–7.38(m,2H),5.99(s,1H),5.09(s,1H),4.9 5(s,1H),4.42(t,J=7.2Hz,2H),2.73(t,J=7.2Hz,2H),2.22–2.12(m,4H),1.71–1.64(m,2H),1.61–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ166.6,144.2,135.3,132.8,130.4,129.5,128.3,124.9,111.0,64.5,32.9,25.88,25.86,22.8,22.1.

[0251] Example 12:

[0252]

[0253] Under an argon atmosphere, conjugated diene compound I-12 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The starting material conversion was 100%, and product II-12 was a colorless oil with a yield of 95%. When photocatalyst 3 was used instead of photocatalyst 2, the yield was 88%. 1 H NMR(400MHz, CDCl3)δ3.72(s,6H),2.60(dd,J=14.2,8.1Hz,2H),2.47–2.37(m,1H),2.32–2.16(m,2H),2. 02–1.94(m,1H),1.89–1.74(m,3H),1.71–1.65(m,1H),1.43(s,3H),1.27–1.12(m,2H),1.03–0.91(m,1H); 13 C NMR (101MHz, CDCl3) δ172.64,172.60,149.7,128.3,53.2,52.41,52.38,38.1,37.6,34.3,33.3,26.9,25.01,24.96,20.1.

[0254] Preparation of conjugated diene compound I-12:

[0255]

[0256] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to ensure inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-12 in 82% yield. 1H NMR (400MHz, CDCl3) δ5.83–5.77(m,1H),5.07(s,1H),4.79(s,1H),3.69(s,6H),2 .91(s,2H),2.15–2.07(m,4H),1.67–1.61(m,2H),1.58–1.52(m,2H),1.35(s,3H); 13 C NMR (101MHz, CDCl3) δ172.5,144.5,136.6,124.7,113.3,53.7,52.3,37.8,26.6,25.7,22.8,22.0,20.0.

[0257] Example 13:

[0258]

[0259] Under an argon atmosphere, conjugated diene compound I-13 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-13 was a colorless oil with a yield of 85%. 1 H NMR (400MHz, CDCl3) δ4.15(td,J=6.8,1.1Hz,2H),3.38–3.29(m,2H),3.26–3.12(m,3H),2.41(dt,J=12.4,3.8Hz,1H),2.29(t,J=6.8Hz,2 H),2.22–2.12(m,2H),1.96–1.90(m,1H),1.87–1.81(m,1H),1.78–1.70(m,2H),1.65–1.59(m,1H),1.20–1.03(m,2H),0.97–0.85(m,1H); 13 C NMR (101MHz, CDCl3) δ203.6,173.8,146.8,129.0,63.5,51.5,37.8,36.5,33.2,28.0,27.3,26.9,25.3,24.9.

[0260] Preparation of conjugated diene compound I-13:

[0261]

[0262] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-13 in 90% yield. 1 H NMR (400MHz, CDCl3) δ5.92(s,1H),5.06(s,1H),4.86(s,1H),4.26(t,J=7.2Hz,2H),3.47–3.35(m,2H ),3.33–3.17(m,3H),2.62(t,J=7.2Hz,2H),2.21–2.10(m,4H),1.71–1.65(m,2H),1.61–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ203.7,173.9,143.8,135.2,124.9,111.0,64.6,51.6,32.7,27.4,25.83,25.79,22.7,22.0.

[0263] Example 14:

[0264]

[0265] Under an argon atmosphere, conjugated diene compound I-14 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (50:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-14 was a colorless oil with a yield of 81%. 1H NMR (400MHz, CDCl3) δ5.91–5.76(m,1H),5.23–5.15(m,1H),5.12–5.04(m,1H),3.93–3.85(m,2H),3.35(t,J=6.7Hz,2H),2.37(dt,J=11.4,3.3Hz,1 H),2.22(dd,J=12.1,4.7Hz,1H),2.16–2.10(m,1H),2.01–1.89(m,3H),1. 84–1.78(m,1H),1.76–1.60(m,5H),1.21–1.05(m,2H),0.98–0.85(m,1H); 13 C NMR (101MHz, CDCl3) δ144.3,135.0,133.4,116.6,71.8,70.0,37.4,36.3,33.4,27.7,27.0,25.3,25.19,25.15.

[0266] Preparation of conjugated diene compound I-14:

[0267]

[0268] I-7 (3.0 mmol, 1.0 equiv), sodium hydride (4.5 mmol, 1.5 equiv), and 20 mL of anhydrous DMF were added to a 100 mL round-bottom flask. The mixture was stirred at 0°C for half an hour, followed by the slow dropwise addition of allyl bromide (3.6 mmol, 1.2 equiv). The reaction mixture was stirred at 25°C for 8 hours. After the reaction was complete, water (100.0 mL) was added to the mixture, and the mixture was extracted three times with diethyl ether (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-14 in 70% yield. 1 H NMR (400MHz, CDCl3) δ5.99–5.86(m,2H),5.31–5.23(m,1H),5.20–5.14(m,1H),4.97(s,1H),4.81(s,1H),4.00–3.93(m,2H) ,3.44(t,J=6.6Hz,2H),2.32(t,J=7.7Hz,2H),2.19–2.11(m,4H),1.79–1.71(m,2H),1.70–1.64(m,2H),1.60–1.53(m,2H); 13C NMR (101MHz, CDCl3) δ148.1,135.5,135.1,124.4,116.6,108.8,71.8,70.1,30.1,29.0,26.0,25.8,22.9,22.2.

[0269] Example 15:

[0270]

[0271] Under an argon atmosphere, conjugated diene compound I-15 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-15 was a yellow oil with a yield of 90%. 1 H NMR(400MHz, CDCl3)δ4.14(t,J=6.6Hz,2H),2.52–2.40(m,3H),2.38–2.17(m,6 H),2.08–1.76(m,7H),1.72–1.66(m,1H),1.31–1.11(m,2H),1.09–0.90(m,1H); 13 C NMR (101MHz, CDCl3) δ173.0,146.6,129.4,83.2,69.0,62.8,37.9,36.6,33.3,32.9,28.2,26.9,25.4,25.0,23.6,17.8.

[0272] Preparation of conjugated diene compound I-15:

[0273]

[0274] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-15 in 87% yield. 1 H NMR (400MHz, CDCl3) δ5.99–5.86(m,2H),5.31–5.23(m,1H),5.20–5.14(m,1H),4.97(s,1H),4.81(s,1H),4.00–3.93(m,2H) ,3.44(t,J=6.6Hz,2H),2.32(t,J=7.7Hz,2H),2.19–2.11(m,4H),1.79–1.71(m,2H),1.70–1.64(m,2H),1.60–1.53(m,2H); 13 C NMR (101MHz, CDCl3) δ173.0,144.1,135.2,124.8,110.8,83.3,69.0,63.9,32.9,32.8,25.84,25.83,23.6,22.8,22.1,17.8.

[0275] Example 16:

[0276]

[0277] Under an argon atmosphere, conjugated diene compound I-16 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-16 was a colorless oil with a yield of 80%. 1H NMR (400MHz, CDCl3) δ4.07–3.97(m,2H),2.41–2.33(m,1H),2.32–2.24(m,2H),2.21–2.12(m,2H),2.01–1. 89(m,4H),1.83–1.78(m,1H),1.74–1.58(m,5H),1.22–1.09(m,2H),1.09–1.05(m,2H),0.97–0.86(m,1H); 13 CNMR (101MHz, CDCl3) δ173.1,144.9,132.5,64.3,37.5,36.3,35.5,33.3,26.9,26.6,25.3,25.1,24.8,16.3,9.0.

[0278] Preparation of conjugated diene compound I-16:

[0279]

[0280] The substrate (3.0 mmol, 1.0 equiv) and 10 mL of ultra-dry tetrahydrofuran were added to a 50 mL single-necked flask. A solution of potassium tert-butoxide in tetrahydrofuran (3.3 mmol, 1.1 equiv) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by continued stirring at 0°C for 0.5 h. After the reaction was complete, a saturated ammonium chloride aqueous solution (50.0 mL) was added to the mixture, and the mixture was extracted three times with diethyl ether (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-16 in 66% yield. 1 H NMR (400MHz, CDCl3) δ5.88(s,1H),4.99(s,1H),4.81(s,1H),4.11(t,J=6.6Hz,2H),2.38–2.35(m,2H),2.34–2.28(m,2 H),2.19–2.12(m,4H),2.09–2.04(m,1H),1.83–1.75(m,2H),1.70–1.64(m,2H),1.61–1.55(m,2H),1.16–1.13(m,2H); 13 C NMR (101MHz, CDCl3) δ173.0,147.3,135.4,124.4,109.3,64.4,35.4,29.8,28.0,25.9,25.8,22.8,22.1,16.3,9.0.

[0281] Example 17:

[0282]

[0283] Under an argon atmosphere, conjugated diene compound I-17 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-17 was a colorless oil with a yield of 85%. 1 H NMR (400MHz, CDCl3) δ4.19(t,J=6.9Hz,2H),3.40(s,2H),2.42(dt,J=12.5,3.6Hz,1H),2.31(t,J=6.9Hz,2H),2.24–2.11( m,2H),1.97–1.90(m,1H),1.88–1.82(m,1H),1.79–1.68(m,2H),1.66–1.59(m,1H),1.20–1.07(m,2H),1.00–0.86(m,1H); 13 C NMR (101MHz, CDCl3) δ162.8,147.2,128.3,112.9,65.1,37.8,36.4,33.1,27.7,26.8,25.2,24.8,24.6.

[0284] Preparation of conjugated diene compound I-17:

[0285]

[0286] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-17 in 84% yield. 1H NMR (400MHz, CDCl3) δ5.90 (s, 1H), 5.07 (s, 1H), 4.88 (s, 1H), 4.30 (t, J = 7.2Hz, 2H), 3.45 (s,2H),2.64(t,J=7.2Hz,2H),2.22–2.08(m,4H),1.71–1.64(m,2H),1.62–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ162.9,143.3,135.1,125.0,113.0,111.4,66.2,32.5,25.8,24.7,22.8,22.0.

[0287] Example 18:

[0288]

[0289] Under an argon atmosphere, conjugated diene compound I-18 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (40:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-18 was a yellow oil with a yield of 56%. 1 H NMR(400MHz, CDCl3)δ3.04–2.90(m,2H),2.50–2.42(m,1H),2.32(s,3H),2.31–2.20(m,4H),2.03–1.96 (m,1H),1.93–1.89(m,1H),1.85–1.74(m,2H),1.72–1.67(m,1H),1.29–1.14(m,2H),1.07–0.94(m,1H); 13 C NMR (101MHz, CDCl3) δ195.9,146.2,131.3,37.7,36.2,33.2,30.6,28.5,27.6,26.9,25.4,25.1.

[0290] Preparation of conjugated diene compound I-18:

[0291]

[0292] Add I-8 (3.0 mmol, 1.0 equiv), potassium thioacetate (6.0 mmol, 2.0 equiv), and 20 mL of acetone to a 100 mL round-bottom flask. Stir the reaction mixture at 25 °C for 12 hours. Filter the precipitate, and concentrate the organic phase under reduced pressure. Purify the residue by rapid silica gel column chromatography to give the corresponding product I-18 in 82% yield. 1 H NMR (400MHz, CDCl3) δ5.96 (s, 1H), 5.02 (s, 1H), 4.85 (s, 1H), 2.98 (t, J = 7.7Hz, 2H), 2.51 (t,J=7.7Hz,2H),2.32(s,3H),2.20–2.11(m,4H),1.70–1.63(m,2H),1.61–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ195.8,146.3,134.8,124.8,110.1,33.7,30.5,28.7,25.81,25.76,22.8,22.0.

[0293] Example 19:

[0294]

[0295] Under an argon atmosphere, conjugated diene compound I-19 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-19 was a colorless oil with a yield of 93%. NMR analysis confirmed a diastereoselectivity of 1:1. 1 H NMR (400MHz, CDCl3) δ7.76–7.67(m,2H),7.58–7.49(m,3H),4.15–4.04(m,1H),3.75–3.64(m,1H),2.47–2.38(m,1H) ,2.37–2.28(m,2H),2.26–2.16(m,2H),2.01–1.94(m,1H),1.89–1.64(m,4H),1.27–1.08(m,2H),1.03–0.92(m,1H); 13C NMR (101MHz, CDCl3) δ147.0,144.72,144.69,132.0,128.9,128.7,125.2,125.1,63.1, 63.0,37.8,36.5,36.4,33.13,33.11,29.33,29.27,26.78,26.77,25.35,25.33,24.9.

[0296] Preparation of conjugated diene compound I-19:

[0297]

[0298] I-8 (3.0 mmol, 1.0 equiv), potassium iodide (0.3 mmol, 0.1 equiv), 20 mL of anhydrous DMF, and sodium benzenesulfinate (3.6 mmol, 1.2 equiv) were added to a 100 mL round-bottom flask. The reaction mixture was stirred at 80 °C for 5 hours. After the reaction was complete, water (100.0 mL) was added to the mixture, and the mixture was extracted three times with ethyl acetate (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-19 in 18% yield. 1 H NMR(400MHz, CDCl3)δ7.75–7.66(m,2H),7.58–7.49(m,3H),5.74(s,1H),5.02(s,1H),4.82(s,1H),4.15–4 .05(m,1H),3.80–3.71(m,1H),2.66–2.51(m,2H),2.13–2.03(m,4H),1.68–1.60(m,2H),1.57–1.50(m,2H); 13 C NMR (101MHz, CDCl3) δ144.7,143.4,135.0,132.0,128.9,125.3,124.9,111.2,64.3,34.0,25.7,22.7,22.0.

[0299] Example 20:

[0300]

[0301] Under an argon atmosphere, conjugated diene compound I-20 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-20 was a colorless oil with a yield of 91%. 1 H NMR (400MHz, CDCl3) δ7.97–7.86(m,2H),7.70–7.63(m,1H),7.61–7.54(m,2H),3.18(t,J=8.2Hz,2H),2.45–2.32(m,3 H),2.25–2.12(m,2H),1.99–1.92(m,1H),1.84–1.73(m,3H),1.69–1.63(m,1H),1.25–1.09(m,2H),0.99–0.89(m,1H); 13 C NMR (101MHz, CDCl3) δ147.0,139.0,133.6,129.2,128.4,128.1,54.3,37.7,36.1,32.9,26.7,25.3,24.8,22.3.

[0302] Preparation of conjugated diene compound I-20:

[0303]

[0304] I-8 (3.0 mmol, 1.0 equiv), potassium iodide (0.3 mmol, 0.1 equiv), 20 mL of anhydrous DMF, and sodium benzenesulfinate (3.6 mmol, 1.2 equiv) were added to a 100 mL round-bottom flask. The reaction mixture was stirred at 80 °C for 5 hours. After the reaction was complete, water (100.0 mL) was added to the mixture, and the mixture was extracted three times with ethyl acetate (20.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-20 in 48% yield. 1H NMR (400MHz, CDCl3) δ7.96–7.89(m,2H),7.66(d,J=7.5Hz,1H),7.62–7.52(m,2H),5.70(s,1H),4.98(s,1H), 4.79(s,1H),3.27–3.19(m,2H),2.69–2.63(m,2H),2.11–2.04(m,4H),1.67–1.60(m,2H),1.57–1.50(m,2H); 13 CNMR (101MHz, CDCl3) δ144.2,139.0,134.4,133.7,129.3,128.1,125.2,110.9,55.8,26.8,25.80,25.76,22.7,21.9.

[0305] Example 21:

[0306]

[0307] Under an argon atmosphere, conjugated diene compound I-21 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-21 was a white solid with a yield of 95%. 1 H NMR(400MHz, CDCl3) δ7.85(dd,J=5.5,3.1Hz,2H),7.72(dd,J=5.5,3.1Hz,2H),4.29–4.16(m,2H),2.50(dt,J=12.6,3.6Hz,1H),2. 39–2.30(m,1H),2.30–2.15(m,1H),2.01–1.90(m,2H),1.85–1.75(m,2H),1.71–1.62(m,1H),1.26–1.15(m,2H),1.06–0.95(m,1H); 13 C NMR (101MHz, CDCl3) δ167.9,148.7,133.8,132.1,126.9,123.1,37.9,36.0,35.5,32.9,26.7,25.3,24.8.

[0308] Preparation of compound III-21:

[0309]

[0310] After obtaining product II-21, the amine compound III-21 can be readily deprotected with hydrazine hydrate. Substrate II-21 (1.0 mmol, 1.0 equiv) was dissolved in methanol in a 100 mL round-bottom flask. Then, 85% hydrazine hydrate aqueous solution (10.0 mmol, 10.0 equiv) was added, and the reaction was stirred at room temperature for 1 hour. Next, 1M potassium hydroxide aqueous solution (10.0 mL) was added, and the reaction was stirred for another hour. The reaction solution was extracted three times with dichloromethane (10.0 mL × 3), and the combined organic phases were dried over anhydrous sodium sulfate. After removing dichloromethane using a rotary evaporator, the solvent was completely removed by vacuum distillation, finally yielding the target product III-21 in 82% yield. 1 H NMR(500MHz, Methanol-d4)δ3.24–3.11(m,2H),2.53(dt,J=12.4,3.7Hz,1H),2.43–2.35(m,1H),2.26–2.20(m,1H) ,2.05–1.99(m,1H),1.99–1.94(m,1H),1.88–1.79(m,2H),1.74–1.68(m,1H),1.30–1.20(m,2H),1.10–1.02(m,1H); 13 C NMR (126MHz, Methanol-d4) δ146.6,134.4,40.2,38.8,35.9,34.3,28.0,26.3,26.1.

[0311] Preparation of conjugated diene compound I-21:

[0312]

[0313] To a 100 mL round-bottom flask, add phenylboronic acid (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-21 in 66% yield. 1H NMR (400MHz, CDCl3) δ7.91–7.83(m,2H),7.76–7.70(m,2H),6.02(s,1H),5.10(s,1H) ,4.75(s,1H),4.50(s,2H),2.23–2.13(m,4H),1.70–1.65(m,2H),1.62–1.55(m,2H); 13 CNMR (101MHz, CDCl3) δ168.1,141.3,134.2,133.9,132.1,125.3,123.3,108.9,39.9,26.0,25.8,22.7,22.0.

[0314] Example 22:

[0315]

[0316] Under an argon atmosphere, conjugated diene compound I-22 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation, purified by silica gel column chromatography using petroleum ether as the eluent. The conversion rate of the starting material was 100%, and the product II-22 was a colorless oil with a yield of 78%. 1 H NMR (400MHz, CDCl3) δ7.31–7.22(m,2H),7.23–7.12(m,3H),2.67–2.55(m,2H),2.46(dt,J=11.2,3.2Hz,1H),2.33–2.25( m,1H),2.25–2.17(m,1H),2.07–1.96(m,3H),1.93–1.86(m,1H),1.85–1.65(m,5H),1.28–1.12(m,2H),1.05–0.95(m,1H); 13 C NMR (101MHz, CDCl3) δ144.2,142.7,133.7,128.4,128.2,125.6,37.5,36.4,35.6,33.5,29.4,28.3,27.0,25.4,25.2.

[0317] Preparation of conjugated diene compound I-22:

[0318]

[0319] To a 100 mL round-bottom flask, add 3.0 mmol (1.0 equiv) of alkyne substrate, 4.5 mmol (1.5 equiv) of phenylboronic acid, 0.3 mmol (0.1 equiv) of acetic acid, 0.009 mmol (0.3 mol%) of tetrakis(triphenylphosphine)palladium, and 20.0 mL of degassed 1,4-dioxane. The reaction mixture was purged three times with argon to ensure inert gas protection, and stirred at 80 °C under argon protection for 14 hours. After the reaction was complete, the mixture was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography to give the product I-22 in 29% yield. 1 H NMR (400MHz, CDCl3) δ7.29–7.25(m,2H),7.21–7.16(m,3H),5.83(s,1H),4.97(s,1H),4.81(s,1H),2.62(t,J= 7.7Hz,2H),2.28(t,J=7.7Hz,2H),2.18–2.09(m,4H),1.82–1.75(m,2H),1.70–1.64(m,2H),1.60–1.53(m,2H); 13 C NMR (101MHz, CDCl3) δ148.4,142.6,135.7,128.4,128.2,125.6,124.3,108.8,35.8,33.3,30.7,26.0,25.8,22.9,22.2.

[0320] Example 23:

[0321]

[0322] Under an argon atmosphere, conjugated diene compound I-23 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-23 was a yellow oil with a yield of 90%. 1H NMR (400MHz, CDCl3) δ7.67(d,J=8.1Hz,2H),7.32(d,J=8.1Hz,2H),4.43(br,1H),4.25(br,1H),3.66–3.54(m,2H),2.70(s,3 H),2.56–2.45(m,2H),2.44(s,3H),2.43–2.32(m,2H),2.26–2.18(m,1H),2.15–2.04(m,1H),2.04–1.96(m,1H),1.46(s,9H); 13 C NMR (101MHz, CDCl3) δ154.7,147.0,143.3,134.3,130.1,129.6,127.4,79.6,51.8,47.7,44.8,36.5,34.7,33.4,28.4,25.4,21.5.

[0323] Preparation of compound III-23:

[0324]

[0325] After obtaining product II-23, the amine compound III-23 can be readily deprotected with trifluoroacetic acid. Compound II-23 (1.0 mmol, 1.0 equiv) was dissolved in dichloromethane, and trifluoroacetic acid (5.0 mL) was added. The reaction mixture was stirred at room temperature for 10 minutes. After 10 minutes, the solvent was removed by vacuum distillation. Subsequently, 20 mL of 10% sodium carbonate aqueous solution was added, and the mixture was extracted twice with dichloromethane (20.0 mL × 2). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to give the target product III-23 in 90% yield. 1 HNMR (400MHz, CDCl3) δ7.67(d,J=8.3Hz,2H),7.32(d,J=8.3Hz,2H),5.35(br,1H),3.66–3.55(m,2H),3.55–3.50(m,1H),3.34–3. 25(m,1H),2.71(s,3H),2.61–2.54(m,2H),2.49(dd,J=13.2,3.6Hz,1H),2.44–2.36(m,5H),2.27–2.18(m,1H),2.06–2.00(m,1H); 13 C NMR (101MHz, CDCl3) δ144.5,143.4,134.3,130.9,129.7,127.4,52.5,47.7,45.8,35.7,34.9,34.2,24.9,21.5.

[0326] Preparation of conjugated diene compound I-23:

[0327]

[0328] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-23 in 71% yield. 1 H NMR (400MHz, CDCl3) δ7.68(d,J=8.2Hz,2H),7.35(d,J=8.2Hz,2H),6.14(s,1H),5.18(s,1H),5.00(s,1H), 4.03(s,2H),3.74(s,2H),3.54(t,J=5.7Hz,2H),2.56(s,3H),2.45(s,3H),2.31–2.27(m,2H),1.48(s,9H); 13 C NMR (101MHz, CDCl3) δ154.5,143.3,140.4,133.1,132.1,129.5,127.3,122.7,114.7,79.3,53.3,43.5,39.3,33.9,28.2,25.6,21.3.

[0329] Example 24:

[0330]

[0331] Under an argon atmosphere, conjugated diene compound I-24 (0.2 mmol, 1.0 equiv), photocatalyst 1 (0.004 mmol, 0.02 equiv), and DCM (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate in an 8:1 eluent. The conversion rate of the starting material was 100%, and the product II-24 was a colorless oil with a yield of 52%.1 H NMR (400MHz, CDCl3) δ7.65–7.59(m,4H),7.34–7.27(m,4H),4.22–4.13(m,1H),4.01–3.91(m,1H),3.59–3.48(m,2H),2.65 (s,3H),2.62–2.56(m,1H),2.45–2.41(m,7H),2.37–2.23(m,2H),2.23–2.16(m,1H),2.06–1.99(m,1H),1.96–1.89(m,1H); 13 C NMR (101MHz, CDCl3) δ144.5,143.4,134.5,134.2,131.1,129.7,129.6,127.4,127.3,53.6,47.8,46.9,35.8,34.9,33.4,25.3,21.50,21.48.

[0332] Preparation of conjugated diene compound I-24:

[0333]

[0334] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-24 in 70% yield. 1 H NMR (400MHz, CDCl3) δ7.70–7.62(m,4H),7.37–7.31(m,4H),6.12(s,1H),5.14(s,1H),4.97(s ,1H),3.74–3.64(m,4H),3.21(t,J=5.7Hz,2H),2.49(s,3H),2.44(s,6H),2.41–2.37(m,2H); 13C NMR (101MHz, CDCl3) δ143.7,143.6,140.4,133.2,132.7,132.0,129.72,129.67,127.8,127.6,121.4,115.7,53.5,45.2,42.8,33.9,26.1,21.5.

[0335] Example 25:

[0336]

[0337] Under an argon atmosphere, conjugated diene compound I-25 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-25 was a yellow oil with a yield of 88%. 1 H NMR (400MHz, CDCl3) δ7.66(d,J=8.2Hz,2H),7.32(d,J=8.2Hz,2H),3.59(q,J=14.8Hz,2H),2.85(dd,J=12.4,5.6Hz ,1H),2.69(s,3H),2.66–2.60(m,2H),2.60–2.49(m,2H),2.48–2.37(m,5H),2.19–2.05(m,1H),2.02–1.95(m,1H); 13 C NMR (101MHz, CDCl3) δ147.0,143.3,134.3,130.2,129.5,127.4,47.1,38.3,36.3,36.0,34.6,29.3,26.0,21.4.

[0338] Preparation of conjugated diene compound I-25:

[0339]

[0340] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-25 in 52% yield. 1 H NMR (400MHz, CDCl3) δ7.68(d,J=8.2Hz,2H),7.34(d,J=8.2Hz,2H),6.30(s,1H),5.20(s,1H),4.96(s, 1H),3.73(s,2H),3.33–3.26(m,2H),2.83–2.76(m,2H),2.55(s,3H),2.50–2.46(m,2H),2.45(s,3H); 13 C NMR (101MHz, CDCl3) δ143.5,142.5,134.7,133.5,129.7,127.6,123.3,114.6,53.7,34.0,26.7,26.2,25.2,21.5.

[0341] Example 26:

[0342]

[0343] Under an argon atmosphere, conjugated diene compound I-26 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (1:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-26 was a yellow oil with a yield of 78%. 1H NMR(400MHz, CDCl3)δ7.66(d,J=7.9Hz,2H),7.34(d,J=7.9Hz,2H),3.63(s,2H),3.41–3.30(m, 1H),3.09–2.96(m,2H),2.94–2.80(m,3H),2.77–2.62(m,5H),2.44(s,3H),2.18–2.10(m,1H); 13 C NMR (101MHz, CDCl3) δ143.7,139.5,135.1,134.0,129.7,127.3,57.1,50.0,47.9,35.4,35.0,34.5,23.3,21.4.

[0344] Preparation of conjugated diene compound I-26:

[0345]

[0346] Compound I-25 (3.0 mmol, 1.0 equiv) was dissolved in 10 mL of anhydrous dichloromethane. The reaction mixture was slowly added to m-CPBA (9.0 mmol, 3.0 equiv) with stirring at 0°C, then allowed to rise naturally to room temperature and stirred for 14 hours. After the reaction was complete, 40.0 mL of ethyl acetate was added for further dilution, followed by washing with 100.0 mL of saturated sodium bisulfite aqueous solution and then with 100.0 mL of saturated sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-26 in 58% yield. 1 H NMR (400MHz, CDCl3) δ7.67(d,J=8.2Hz,2H),7.36(d,J=8.2Hz,2H),6.09(s,1H),5.30(s,1H),5.12(s,1H) ,3.77–3.74(m,2H),3.73(s,2H),3.16(t,J=6.4Hz,2H),2.96(t,J=6.4Hz,2H),2.56(s,3H),2.45(s,3H); 13 C NMR (101MHz, CDCl3) δ143.6,140.5,133.7,129.6,127.3,118.0,117.6,53.6,50.0,46.7,33.9,26.7,21.3.

[0347] Example 27:

[0348]

[0349] Under an argon atmosphere, conjugated diene compound I-27 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:acetone = 2:1 as the eluent. The conversion rate of the starting material was 100%, and the product II-27 was a colorless oil with a yield of 50%. 1 H NMR (400MHz, CDCl3) δ7.91–7.77(m,2H),7.78–7.67(m,2H),5.91(s,1H),5.14(s,1H),4.83(s,1H),4.49(s,2H ),3.97(s,1H),2.59–2.39(m,2H),2.35–2.25(m,1H),2.21–2.13(m,1H),1.98–1.90(m,1H),1.78–1.64(m,2H); 13 CNMR (101MHz, CDCl3) δ168.1,140.7,134.0,134.0,132.0,123.3,122.0,110.4,66.4,39.9,34.7,30.8,24.3.

[0350] Preparation of conjugated diene compound I-27:

[0351]

[0352] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-27 in 50% yield. 1H NMR (400MHz, CDCl3) δ7.91–7.77(m,2H),7.78–7.67(m,2H),5.91(s,1H),5.14(s,1H),4.83(s,1H),4.49(s,2H ),3.97(s,1H),2.59–2.39(m,2H),2.35–2.25(m,1H),2.21–2.13(m,1H),1.98–1.90(m,1H),1.78–1.64(m,2H); 13 C NMR (101MHz, CDCl3) δ168.1,140.7,134.0,134.0,132.0,123.3,122.0,110.4,66.4,39.9,34.7,30.8,24.3.

[0353] Example 28:

[0354]

[0355] Under an argon atmosphere, conjugated diene compound I-28 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation, purified by silica gel column chromatography using petroleum ether as the eluent. The conversion rate of the starting material was 100%, and the product II-28 was a colorless oil with a yield of 82%. 1 H NMR (400MHz, CDCl3) δ2.48–2.36(m,2H),2.27–2.19(m,2H),1.82–1.67(m,8H),1.25–1.13(m,6H); 13 C NMR (101MHz, CDCl3) δ137.8,42.4,27.6,27.1,24.81,24.80.

[0356] Preparation of conjugated diene compound I-28:

[0357]

[0358] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-28 in 51% yield. 1 H NMR (400MHz, CDCl3) δ5.78(s,2H),2.20–2.15(m,4H),2.15–2.08(m,4H),1.70–1.63(m,4H),1.60–1.54(m,4H); 13 C NMR (101MHz, CDCl3) δ136.8,121.3,25.9,25.5,23.1,22.5.

[0359] Example 29:

[0360]

[0361] Under an argon atmosphere, conjugated diene compound I-29 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (40:1) as the eluent. The conversion rate of the starting material was 100%, and product II-29 was a yellow oil with a yield of 91%. 1 H NMR (400MHz, CDCl3) δ4.32–4.11(m,2H),2.64–2.45(m,4H),2.33–2.25(m,1H),2.20–2.12(m, 1H),2.11–2.00(m,1H),1.88–1.75(m,3H),1.74–1.67(m,1H),1.46(s,9H),1.25–1.14(m,3H); 13C NMR (101MHz, CDCl3) δ155.0,140.2,134.2,79.1,47.8,44.9,41.5,40.2,28.3,27.5,26.8,24.8,24.7,24.5.

[0362] Preparation of conjugated diene compound I-29:

[0363]

[0364] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-29 in 58% yield. 1 H NMR(400MHz, CDCl3)δ5.79(s,1H),5.63(s,1H),4.03–3.94(m,2H),3.51(t,J=5.8Hz,2H), 2.33–2.23(m,2H),2.22–2.11(m,4H),1.71–1.63(m,2H),1.62–1.53(m,2H),1.47(s,9H); 13 C NMR (101MHz, CDCl3) δ154.7,135.6,135.4,122.8,117.2,79.3,43.5,40.1,28.4,25.7,25.4,25.2,22.8,22.2.

[0365] Example 30:

[0366]

[0367] Under an argon atmosphere, conjugated diene compound I-30 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with 6 W blue light at 455-460 nm for 36 hours. The reaction solution was concentrated by rotary evaporation, purified by silica gel column chromatography under an LED lamp, using petroleum ether:ethyl acetate in a 4:1 eluent. The conversion rate of the starting material was 100%, and product II-30 was a yellow oil with a yield of 80%. 1 H NMR (400MHz, CDCl3) δ4.18(dd,J=10.5,6.8Hz,1H),4.01(dd,J=10.5,6.0Hz,1H),3.30(t,J=10.7Hz,1H),3.18(td,J=10.9,4.0Hz,1H) ,2.74–2.65(m,1H),2.57–2.48(m,1H),2.33–2.27(m,1H),2.24–2.11(m,2H),1.88–1.79(m,2H),1.76–1.66(m,2H),1.25–1.16(m,3H); 13 C NMR (101MHz, CDCl3) δ140.0,133.0,72.0,68.2,42.2,40.6,27.5,26.8,26.3,24.7,24.6.

[0368] Preparation of conjugated diene compound I-30:

[0369]

[0370] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-30 in 40% yield. 1H NMR(400MHz, CDCl3)δ5.79(s,1H),5.67(s,1H),4.27–4.20(m,2H),3.85–3.78(m, 2H),2.31–2.22(m,2H),2.18–2.11(m,4H),1.70–1.63(m,2H),1.62–1.55(m,2H); 13 C NMR (101MHz, CDCl3) δ135.2,134.4,122.5,118.9,65.8,64.5,25.6,25.5,24.9,22.7,22.3.

[0371] Example 31:

[0372]

[0373] Under an argon atmosphere, conjugated diene compound I-31 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and DCM (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using n-pentane:diethyl ether = 100:1 as the eluent. The conversion rate of the starting material was 100%, and product II-31 was a yellow oily substance with a yield of 69%. 1 H NMR (400MHz, CD2Cl2) δ2.70–2.62(m,1H),2.56–2.36(m,6H),2.25–2.16(m,1H),2.01–1.91(m,1H),1.74–1.59(m,4H),1.17–1.06(m,3H); 13 C NMR (101MHz, CD2Cl2) δ141.0,135.1,44.4,43.1,32.3,30.3,28.1,27.3,26.2,25.0,24.7.

[0374] Preparation of conjugated diene compound I-31:

[0375]

[0376] To a 100 mL round-bottom flask, add the corresponding boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL). Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated olefin (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-31 in 21% yield. 1 H NMR(400MHz, CDCl3)δ5.90(s,1H),5.82(s,1H),3.31–3.20(m,2H),2.78(t,J=5.9H z,2H),2.51–2.43(m,2H),2.18–2.10(m,4H),1.70–1.63(m,2H),1.61–1.54(m,2H); 13 CNMR (101MHz, CDCl3) δ138.0,136.8,122.4,117.8,26.4,26.3,25.8,25.7,25.6,23.0,22.3.

[0377] Example 32:

[0378]

[0379] Under an argon atmosphere, conjugated diene compound I-32 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (4:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-32 was a yellow oil with a yield of 86%. NMR analysis confirmed a diastereoselectivity of 1:1. 1H NMR (400MHz, CDCl3) δ7.72–7.63(m,3H),7.43–7.34(m,1H),7.17–7.04(m,2H),4. 20–4.04(m,2H),3.87(s,3H),3.81(q,J=7.1Hz,1H),2.44–2.34(m,1H),2.30–2.22 (m,2H),2.22–2.09(m,2H),1.96–1.86(m,1H),1.86–1.77(m,1H),1.75–1.66(m,2H ),1.66–1.58(m,1H),1.56(d,J=7.1Hz,3H),1.22–1.00(m,2H),0.95–0.79(m,1H); 13 C NMR (101MHz, CDCl3) δ174.5,157.5,146.4,135.7,133.6,129.3,129.2,128.8,127.00,126.99,126.14,126.13,125.84,125.8 3,118.8,105.4,63.1,55.1,45.4,37.7,36.5,36.4,33.14,33.09,28.1,28.0,26.82,26.79,25.27,25.25,25.0,18.52,18.50.

[0380] Preparation of conjugated diene compound I-32:

[0381]

[0382] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-32 in 88% yield. 1H NMR (400MHz, CDCl3) δ7.71–7.64(m,3H),7.42–7.38(m,1H),7.15–7.08(m,2H),5.87(s,1H),4.95(s,1H),4.75(s,1H),4.16(td,J=7 .4,2.6Hz,2H),3.88(s,3H),3.83(q,J=7.2Hz,1H),2.52(t,J=7.2Hz,2H),2.13–2.06(m,4H),1.67–1.60(m,2H),1.58–1.50(m,5H); 13 C NMR (101MHz, CDCl3) δ174.6,157.5,143.9,135.7,135.1,133.6,129.2,128.8,127.0,12 6.2,125.9,124.8,118.9,110.9,105.5,64.2,55.2,45.4,32.7,25.8,22.7,22.0,18.5.

[0383] Example 33:

[0384]

[0385] Under an argon atmosphere, conjugated diene compound I-33 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (20:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-33 was a yellow oil with a yield of 82%. NMR analysis confirmed a diastereoselectivity of 1:1:1:1. 1H NMR(400MHz, CDCl3)δ7.12(d,J=7.8Hz,2H),7.00(d,J=7.8Hz,2H),4.12–3.96(m,2H),3 .59(q,J=7.1Hz,1H),2.36(d,J=7.2Hz,2H),2.34–2.28(m,1H),2.19(t,J=6.1Hz,2H),2. 16–2.05(m,2H),1.91–1.83(m,1H),1.80–1.72(m,2H),1.71–1.62(m,2H),1.61–1.55(m, 1H),1.40(d,J=7.1Hz,3H),1.15–1.00(m,2H),0.90–0.83(m,1H),0.82(d,J=6.6Hz,6H); 13 C NMR (101MHz, CDCl3) δ174.7,146.4,140.4,137.8,129.5,129.2,127.1,63.12,63.11,45.2,45.0,3 7.8,36.56,36.55,33.21,33.19,30.1,28.07,28.06,26.91,26.87,25.33,25.31,25.0,22.3,18.6.

[0386] Preparation of conjugated diene compound I-33:

[0387]

[0388] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-33 in 98% yield. 1H NMR (400MHz, CDCl3) δ7.19(d,J=7.8Hz,2H),7.08(d,J=7.8Hz,2H),5.88(s,1H) ,4.97(s,1H),4.75(s,1H),4.15(t,J=7.2Hz,2H),3.67(q,J=7.1Hz,1H),2.53(t ,J=7.2Hz,2H),2.44(d,J=7.1Hz,2H),2.15–2.08(m,4H),1.89–1.79(m,1H),1.6 7–1.61(m,2H),1.59–1.52(m,2H),1.48(d,J=7.1Hz,3H),0.89(d,J=6.4Hz,6H); 13 C NMR (101MHz, CDCl3) δ174.7,143.9,140.4,137.8,135.1,129.2,127.1,124.7,110.9,64.1,45.1,45.0,32.8,30.1,25.8,22.8,22.3,22.0,18.5.

[0389] Example 34:

[0390]

[0391] Under an argon atmosphere, conjugated diene compound I-34 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (4:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-34 was a yellow oil with a yield of 35%. 1H NMR (400MHz, CDCl3) δ7.66(d,J=8.1Hz,2H),7.47(d,J=8.1Hz,2H),6.96(d,J=2.5Hz,1H),6.8 6(d,J=9.0Hz,1H),6.67(dd,J=9.0,2.5Hz,1H),4.16(t,J=6.9Hz,2H),3.84(s,3H),3.65(s,2H ),2.45–2.40(m,1H),2.38(s,3H),2.35–2.29(m,2H),2.26–2.13(m,2H),2.01–1.93(m,1H),1 .89–1.82(m,1H),1.82–1.70(m,2H),1.70–1.62(m,1H),1.26–1.11(m,2H),0.99–0.89(m,1H); 13 C NMR (101MHz, CDCl3) δ170.8,168.3,156.0,146.6,139.2,135.9,133.9,131.1,130.8,130.7,129.2, 129.1,114.9,112.7,111.6,101.3,63.6,55.7,37.9,36.6,33.3,30.4,28.2,26.9,25.4,25.0,13.3.

[0392] Preparation of conjugated diene compound I-34:

[0393]

[0394] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-34 in 92% yield. 1H NMR (400MHz, CDCl3) δ7.66 (d, J = 8.5 Hz, 2H), 7.46 (d, J = 8.5 Hz, 2H), 6.96 (d, J = 2. 6Hz,1H),6.87(d,J=9.0Hz,1H),6.66(dd,J=9.0,2.6Hz,1H),5.88(s,1H),4.98(s ,1H),4.78(s,1H),4.20(t,J=7.2Hz,2H),3.83(s,3H),3.65(s,2H),2.58(t,J=7 .2Hz,2H),2.38(s,3H),2.16–2.08(m,4H),1.68–1.60(m,2H),1.59–1.52(m,2H); 13 C NMR (101MHz, CDCl3) δ170.8,168.2,156.0,143.8,139.1,135.8,135.1,133.9,131.1,130.7,130.6 ,129.0,124.8,114.9,112.6,111.5,110.9,101.3,64.3,55.6,32.8,30.3,25.8,22.7,22.0,13.3.

[0395] Example 35:

[0396]

[0397] Under an argon atmosphere, conjugated diene compound I-35 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-35 was a white solid with a yield of 45%. 1H NMR (400MHz, CDCl3) δ8.16(d,J=2.3Hz,1H),8.09(dd,J=8.9,2.3Hz,1H),7.02(d,J =8.9Hz,1H),4.36(t,J=6.6Hz,2H),3.90(d,J=6.4Hz,2H),2.76(s,3H),2.57–2.49 (m,1H),2.49–2.40(m,2H),2.34–2.17(m,3H),2.04–1.93(m,2H),1.84–1.77(m,2H ),1.73–1.65(m,1H),1.31–1.14(m,2H),1.09(d,J=6.7Hz,7H),1.06–0.94(m,1H); 13 C NMR (101MHz, CDCl3) δ167.1,162.4,161.9,161.1,146.9,132.5,132.0,129.1,126.0,121.8, 115.3,112.6,102.9,75.6,63.8,37.9,36.7,33.2,28.2,28.1,26.9,25.4,25.0,19.0,17.4.

[0398] Preparation of conjugated diene compound I-35:

[0399]

[0400] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-35 in 75% yield. 1H NMR (400MHz, CDCl3) δ8.16(d,J=2.3Hz,1H),8.08(dd,J=8.8,2.3Hz,1H),7.01(d,J=8.8Hz,1H),5.97(s,1H),5.10(s,1H),4.94(s,1H),4.39(t,J=7. 1Hz,2H),3.90(d,J=6.5Hz,2H),2.75(s,3H),2.71(t,J=7.1Hz,2H),2.24– 2.14(m,5H),1.71–1.65(m,2H),1.62–1.55(m,2H),1.09(d,J=6.7Hz,6H); 13 C NMR (101MHz, CDCl3) δ167.1,162.4,161.9,161.0,143.9,135.2,132.4,132.0,125.9,124.9,1 21.9,115.3,112.5,111.2,102.9,75.6,64.8,32.8,28.1,25.9,25.8,22.8,22.0,19.0,17.4.

[0401] Example 36:

[0402]

[0403] Under an argon atmosphere, conjugated diene compound I-36 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:acetone (2:1) as the eluent. The conversion rate of the starting material was 100%, and product II-36 was a white solid with a yield of 88%. NMR analysis confirmed a diastereoselectivity of 1:1. 1H NMR (400MHz, CDCl3) δ7.48–7.06(m,10H),6.61–6.26(m,1H),5.65–5.35(m,1 H),5.17–4.98(m,2H),4.58–4.34(m,2H),4.26–4.03(m,2H),3.14–2.96(m,2H ),2.52–2.39(m,1H),2.38–2.13(m,4H),2.03–1.96(m,1H),1.92–1.85(m,1H) ,1.85–1.72(m,2H),1.73–1.64(m,1H),1.36–1.10(m,5H),1.04–0.90(m,1H); 13 C NMR (101MHz, CDCl3) δ172.4,172.3,170.3,170.1,155.8,146.9,146.84,146.83,136.3,13 6.2,136.1,129.28,129.25,128.8,128.60,128.55,128.4,128.1,127.9,126.9,66.9,63.8 8,63.86,63.83,63.82,56.1,55.9,48.2,48.0,38.8,38.5,37.87,37.86,36.6,36.5,33.21,33.20,33.18,28.02,28.00,27.99,27.96,26.89,26.86,25.35,25.33,24.9,18.3,18.1.

[0404] Preparation of conjugated diene compound I-36:

[0405]

[0406] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-36 in 68% yield. 1H NMR (400MHz, CDCl3) δ7.36–7.27(m,6H),7.26–7.14(m,4H),6.48–6.14(br,1H),5.9 3–5.85(m,1H),5.53–5.25(br,1H),5.11–5.06(m,2H),5.04(d,J=7.4Hz,1H),4.83(d ,J=9.7Hz,1H),4.52–4.33(m,2H),4.24–4.13(m,2H),3.14–3.00(m,2H),2.62–2.52 (m,2H),2.17–2.11(m,4H),1.70–1.63(m,2H),1.60–1.53(m,2H),1.33–1.19(m,3H); 13 C NMR (101MHz, CDCl3) δ172.4,172.3,170.2,170.0,155.8,143.7,136.3,136.1,135.2,135.1,129.31,129.29,128.7,128.6,128.5,128. 1,128.0,127.0,124.9,111.1,67.0,64.8,56.2,56.0,48.2,48.0,38.9,38.5,32.7,25.85,25.84,25.82,25.80,22.8,22.0,18.4,18.2.

[0407] Example 37:

[0408]

[0409] Under an argon atmosphere, conjugated diene compound I-37 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and the product II-37 was a colorless oil with a yield of 90%. NMR analysis confirmed a diastereoselectivity of 1:1. 1H NMR (400MHz, CDCl3) δ4.21 (t, J=7.0Hz, 2H), 4.08 (dd, J=16.3, 11.4Hz, 2H), 3.16 (td ,J=10.5,4.1Hz,1H),2.55–2.42(m,1H),2.38–2.16(m,5H),2.09–2.04(m,1H),2.03 –1.97(m,1H),1.94–1.87(m,1H),1.85–1.76(m,2H),1.71–1.61(m,3H),1.37–1.14( m,4H),1.03–0.95(m,2H),0.93–0.89(m,7H),0.88–0.84(m,1H),0.81–0.78(m,3H); 13 C NMR (101MHz, CDCl3) δ170.7,146.6,129.1,80.0,65.85,65.83,62.9,48.0,39.8,37 .8,36.5,34.3,33.2,31.4,28.1,26.9,25.32,25.30,24.9,23.2,22.2,20.9,16.1.

[0410] Preparation of conjugated diene compound I-37:

[0411]

[0412] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-37 in 90% yield. 1H NMR (400MHz, CDCl3) δ5.93 (s, 1H), 5.04 (s, 1H), 4.86 (s, 1H), 4.24 (t, J = 7.3Hz, 2H) ,4.16–4.04(m,2H),3.16(td,J=10.6,4.1Hz,1H),2.61(t,J=7.3Hz,2H),2.34–2.2 7(m,1H),2.19–2.12(m,4H),2.09–2.04(m,1H),1.70–1.56(m,6H),1.36–1.27(m,2 H),1.00–0.95(m,1H),0.93–0.89(m,7H),0.87–0.83(m,1H),0.80(d,J=7.1Hz,3H); 13 CNMR(101MHz,CDCl3)δ170.7,143.8,135.1,124.8,110.8,80.0,65.9,64.0, 48.0,39.8,34.3,32.7,31.4,25.7,25.3,23.2,22.7,22.2,22.0,20.9,16.1.

[0413] Example 38:

[0414]

[0415] Under an argon atmosphere, conjugated diene compound I-38 (0.2 mmol, 1.0 equiv), photocatalyst 1 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:ethyl acetate (10:1) as the eluent. The conversion rate of the starting material was 100%, and product II-38 was a colorless oil with a yield of 62%. 1H NMR (400MHz, CDCl3) δ7.71(d,J=7.8Hz,2H),7.24(d,J=7.8Hz,2H),6.67(d,J=4.0Hz,1H ),6.10(d,J=4.0Hz,1H),4.21(t,J=6.9Hz,2H),3.95(s,3H),3.70(s,2H),2.48–2.43(m ,1H),2.42(s,3H),2.35(t,J=7.0Hz,2H),2.30–2.18(m,2H),2.03–1.96(m,1H),1.90–1 .84(m,1H),1.83–1.74(m,2H),1.71–1.65(m,1H),1.27–1.11(m,2H),1.03–0.90(m,1H); 13 C NMR (101MHz, CDCl3) δ185.8,169.3,146.8,141.8,137.3,134.5,131.3,129.4,129.0, 128.6,122.2,109.4,63.8,37.9,36.6,33.2,33.1,32.9,28.1,26.9,25.3,25.0,21.5.

[0416] Preparation of conjugated diene compound I-38:

[0417]

[0418] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-38 in 88% yield. 1H NMR (400MHz, CDCl3) δ7.71(d,J=7.8Hz,2H),7.24(d,J=7.8Hz,2H),6.67(d,J=4.0Hz,1H),6.10(d,J=4.0Hz,1H),5.91(s,1H),5.03(s,1H),4.82(s,1H ),4.24(t,J=7.1Hz,2H),3.96–3.91(m,3H),3.70(s,2H),2.60(t,J=7.1Hz, 2H),2.42(s,3H),2.18–2.11(m,4H),1.70–1.63(m,2H),1.62–1.54(m,2H); 13 C NMR (101MHz, CDCl3) δ185.8,169.3,143.7,141.8,137.3,135.1,134.5,131.3,129.4 ,128.6,124.9,122.2,111.1,109.4,64.7,33.1,32.9,32.8,25.8,22.8,22.0,21.5.

[0419] Example 39:

[0420]

[0421] Under an argon atmosphere, conjugated diene compound I-39 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was concentrated by rotary evaporation and purified by silica gel column chromatography using petroleum ether:acetone (1:1) as the eluent. The conversion rate of the starting material was 100%, and product II-39 was a yellow solid with a yield of 88%. NMR analysis confirmed a diastereoselectivity of 1:1. 1 H NMR(400MHz, CDCl3)δ4.13(t,J=7.0Hz,2H),2.96–2.83(m,3H),2.50–2.45(m,1H),2.41–2.24(m,10H),2.21–2.08(m,4H),2.05–1.91(m,6H),1 .86–1.75(m,4H),1.70–1.59(m,2H),1.41(s,3H),1.40–1.33(m,2H),1. 31–1.15(m,4H),1.08(s,3H),1.03–0.94(m,1H),0.85(d,J=6.6Hz,3H); 13CNMR(101MHz, CDCl3)δ211.8,208.9,208.6,173.9,146.4,129.4,62.6,56.8,51.6,48.9,46.7,45.6,45.4,44.9,42. 7,38.5,37.8,36.6,36.4,35.9,35.4,35.1,33.2,31.4,30.4,28.1,27.5,26.9,25.3,25.02,24.97,21.8,18.5,11.7.

[0422] Preparation of conjugated diene compound I-39:

[0423]

[0424] Compound I-6 (3.0 mmol, 1.0 equiv), DMAP (0.3 mmol, 0.1 equiv), and the corresponding carboxylic acid (4.5 mmol, 1.5 equiv) were dissolved in 20 mL of anhydrous dichloromethane. A solution of EDCI (4.5 mmol, 1.5 equiv) in DCM (10.0 mL) was slowly added dropwise to the reaction mixture with stirring at 0°C, followed by natural warming to room temperature and continued stirring for 12 hours. After the reaction was complete, water (50.0 mL) was added to the mixture, and the mixture was extracted three times with dichloromethane (50.0 mL × 3). The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to give the corresponding product I-39 in 61% yield. 1 H NMR (400MHz, CDCl3) δ5.92(s,1H),5.04(s,1H),4.86(s,1H),4.16(t,J=7.3Hz,2H),2.95–2.80(m,3H),2.58(t,J=7.3Hz,2H),2.41–2.1 2(m,14H),2.06–1.93(m,4H),1.89–1.80(m,2H),1.70–1.56(m,5H),1.40(s,3H),1.39–1.24(m,4H),1.07(s,3H),0.85(d,J=6.6Hz,3H); 13C NMR (101MHz, CDCl3) δ211.9,209.0,208.6,174.0,144.1,135.2,124.8,110.7,63.7,56.8,51.7,48.9,46.8,45.6 ,45.5,44.9,42.7,38.6,36.4,36.0,35.5,35.2,32.8,31.5,30.4,27.6,25.8,25.1,22.8,22.1,21.9,18.6,11.8.

[0425] Comparative Example 1:

[0426]

[0427] Under an argon atmosphere, conjugated diene compound I-40 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 1H NMR testing confirmed that no target electrocyclization products were generated.

[0428] Preparation of conjugated diene compound I-40:

[0429]

[0430] Add boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL) to a 100 mL round-bottom flask. Purge the reaction system three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-40 in 72% yield. 1H NMR (400MHz, CDCl3) δ7.69(d,J=8.1Hz,2H),7.34(d,J=8.1Hz,2H),6.14(s,1H),5.07(s,1H), 5.03(s,1H),3.76(s,2H),2.59(s,3H),2.50–2.45(m,4H),2.44(s,3H),1.89(p,J=7.7Hz,2H); 13 C NMR (101MHz, CDCl3) δ143.3,140.5,138.0,133.6,129.6,129.3,127.4,115.0,53.6,34.2,33.5,32.8,22.5,21.4.

[0431] Comparative Example 2:

[0432]

[0433] Under an argon atmosphere, conjugated diene compound I-41 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 1H NMR testing confirmed that no target electrocyclization products were generated.

[0434] Preparation of conjugated diene compound I-41:

[0435]

[0436] Add boric acid compound (4.5 mmol, 1.5 equiv), potassium carbonate (9.0 mmol, 3.0 equiv), bis(triphenylphosphine)palladium dichloride (0.3 mmol, 10 mol%), degassed THF (30.0 mL), and degassed water (10.0 mL) to a 100 mL round-bottom flask. Purge the reaction mixture three times with argon to achieve inert gas protection, then add the corresponding brominated alkene (3.0 mmol, 1.0 equiv) under an argon atmosphere. Stir the reaction mixture at 25°C under argon protection for 12 hours. After the reaction is complete, add saturated ammonium chloride aqueous solution (50.0 mL) to the mixture and extract three times with ethyl acetate (50.0 mL × 3). Combine the organic phases, dry over anhydrous sodium sulfate, concentrate under reduced pressure, and purify the residue by silica gel column chromatography to give the corresponding product I-41 in 68% yield. 1H NMR (400MHz, CDCl3) δ7.68(d,J=8.1Hz,2H),7.33(d,J=8.1Hz,2H),6.11(t,J=6.8Hz,1H),5.11(s,1H),4.91(s,1H), 3.72(s,2H),2.56(s,3H),2.44(s,3H),2.37–2.33(m,2H),2.24–2.18(m,2H),1.79–1.73(m,2H),1.54–1.45(m,4H); 13 C NMR (101MHz, CDCl3) δ144.3,143.3,142.3,133.8,130.9,129.6,127.5,113.1,53.7,34.0,32.4,29.8,28.5,26.5,26.4,21.5.

[0437] Comparative Example 3 is not a suitable photocatalyst for this reaction.

[0438]

[0439] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv), photocatalyst [Ru(bpy)3](PF6)2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 ¹H NMR testing confirmed that the target electrocyclic product II-4 was not formed.

[0440] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv), photocatalyst [Ru(bpz)3](PF6)2 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 ¹H NMR testing confirmed that the target electrocyclic product II-4 was not formed.

[0441] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv), photocatalyst Ir(dtbbpy)(ppy)2PF6 (0.004 mmol, 0.02 equiv), and THF (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 ¹H NMR testing confirmed that the target electrocyclic product II-4 was not formed.

[0442] Comparative Example 4

[0443]

[0444] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv), photocatalyst 2 (0.004 mmol, 0.02 equiv), and acetic acid (4 mL) were added to the reaction flask. The mixture was stirred at room temperature and irradiated with a 6-watt blue LED lamp (455-460 nm) for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 ¹H NMR testing confirmed that the target electrocyclic product II-4 was not formed.

[0445] Comparative Example 5

[0446]

[0447] Under an argon atmosphere, conjugated diene compound I-4 (0.2 mmol, 1.0 equiv) and THF (4 mL) were added to a reaction flask. The mixture was stirred at room temperature and irradiated with a 20-watt light source at a wavelength of 255 nm for 36 hours. The reaction solution was then concentrated to dryness by rotary evaporation. 1 ¹H NMR testing confirmed that the target electrocyclic product II-4 was not formed.

[0448] The relevant information for the 255nm lamp source is as follows:

[0449] brand model power wavelength 255nm light source Nuozhi Technology RLH-21 / 24 20W 255nm

[0450] Finally, it should be noted that the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a cyclobutene compound, comprising the following steps: In a solvent, in the presence of a photocatalyst, and under visible light irradiation, conjugated diene compound I undergoes a cyclization reaction to yield cyclobutene compound II; The first carbon-carbon double bond in the conjugated diene of the conjugated diene compound I is located in a six-membered non-aromatic ring, and the second carbon-carbon double bond is not on the same ring as the first carbon-carbon double bond. The cyclobutene compound II contains a six-membered non-aromatic ring-p-cyclobutene structure; in the six-membered non-aromatic ring-p-cyclobutene structure, the non-aromatic six-membered ring and the cyclobutene share two carbon atoms to form a fused ring; and among the shared carbon atoms, only one is an unsaturated carbon in a carbon-carbon double bond. In the conjugated diene compound I and cyclobutene compound II, the six-membered non-aromatic ring is a carbocyclic ring or a carbon heterocyclic ring; in the carbon heterocyclic ring, the number of heteroatoms or heterogroups is 1, 2, or 3, and the heteroatoms or heterogroups are independently -O-, -S-, -NH-, or -N(R) x One or more of - and -S(=O)2-; R x It is an amino protecting group; In the conjugated diene compound I and cyclobutene compound II, the six-membered non-aromatic ring may or may not have substituents.

2. The preparation method according to claim 1, characterized in that, It meets one or more of the following conditions: (1) The first carbon-carbon double bond and the second carbon-carbon double bond are conjugated; (2) The photocatalyst is a metal iridium complex or an organic photocatalyst; The organic photocatalyst is preferably photocatalyst 3 or a tricyclic organic photocatalyst; the tricyclic organic photocatalyst is preferably photocatalyst 6, 7 or 8. (3) In the conjugated diene compound I, only the first carbon-carbon double bond and the second carbon-carbon double bond participate in the ring-closing reaction; (4) The second carbon-carbon double bond is an intracyclic double bond of another six-membered non-aromatic ring, or the second carbon-carbon double bond is a non-intracyclic double bond. (5) The solvent is one or more of the following: haloalkanes, ethers, nitriles, ketones, alcohols, alkanes, sulfoxides, esters, amides, and aromatics. (6) The ratio of the amount of the conjugated diene compound I to the volume of the solvent is 0.01-1.0 mol / L, preferably 0.01-0.1 mol / L, for example 0.05 mol / L; (7) The photocatalyst is a photocatalyst with a triplet energy >55 kcal / mol; (8) The ratio of the amount of the photocatalyst to the amount of the conjugated diene compound I is (0.005-0.05):1, for example, 0.02:1; (9) The ratio of the amount of the photocatalyst to the volume of the solvent is 0.0002-0.02 mol / L, preferably 0.0002-0.002 mol / L, for example 0.001 mol / L; (10) The wavelength of the visible light is 410nm±60nm; the wavelength of the visible light is preferably 455nm±15nm or 375±20nm, more preferably 455-460nm or 385-390nm. (11) The power of the visible light source is 1-100 watts, for example 6 watts; (12) The cyclization reaction is an intramolecular reaction that occurs in the conjugated diene compound I; (13) The cyclization reaction is performed at a temperature of 10-40°C, preferably 20-30°C, for example 25°C; (14) The cyclization reaction is carried out under the protection of an inert gas; the inert gas is preferably argon and / or nitrogen; (15)R x It is a sulfonyl amino protecting group, an acyl amino protecting group, or a carbonate amino protecting group; The sulfonyl amino protecting group is preferably methanesulfonyl, trifluoromethanesulfonyl, p-methylbenzenesulfonyl, benzenesulfonyl, p-fluorobenzenesulfonyl, or p-bromobenzenesulfonyl; The acyl amino protecting group is preferably benzoyl, acetyl, trifluoroacetyl, or pivaloyl; The preferred amino protecting group of the carbonate is 9-fluorenylmethylcarbonyl, 2,2,2-trichloroethoxycarbonyl, tert-butoxycarbonyl, benzyloxycarbonyl or allyloxycarbonyl; Preferably, R x It can be p-toluenesulfonyl, tert-butoxycarbonyl, acetyl, benzoyl, benzyloxycarbonyl, p-bromobenzenesulfonyl or methanesulfonyl, preferably p-toluenesulfonyl or tert-butoxycarbonyl; (16) In the conjugated diene compound I, the six-membered non-aromatic ring is (17) In the cyclobutene compound II, the "six-membered non-aromatic ring--cyclobutene structure" is (18) In the conjugated diene compound I and cyclobutene compound II, when the six-membered non-aromatic ring is a carbon heterocycle, the number of heteroatoms or heteroatomic groups is 1.

3. The preparation method according to claim 2, characterized in that, It meets one or more of the following conditions: (1) The halohydrocarbon solvent is a C444 substituted with one or more halogens. 1-6 Alkanes, preferably C4 substituted with one or more chlorine atoms. 1-6 Alkanes, such as dichloromethane; (2) The ether solvent is a cyclic ether solvent, such as tetrahydrofuran; (3) The nitrile solvent is acetonitrile; (4) The ketone solvent is acetone; (5) The alcohol solvent is C 1-6 Alcohol solvents, such as methanol; (6) The alkane solvent is C 1-10 Alkane solvents, such as n-hexane; (7) The sulfoxide solvent is dimethyl sulfoxide; (8) The ester solvent is ethyl acetate; (9) The amide solvent is N,N-dimethylacetamide; (10) The aromatic hydrocarbon solvent is toluene; (11) The solvent is a halogenated hydrocarbon solvent or an ether solvent, such as dichloromethane and tetrahydrofuran; (12) The photocatalyst with triplet energy > 55 kcal / mol is preferably a metal iridium complex with triplet energy > 55 kcal / mol or an organic photocatalyst with triplet energy > 55 kcal / mol; the organic photocatalyst is a photocatalyst that can catalyze photoreactions and does not contain metal ions; Preferably, the iridium complex with triplet energy >55 kcal / mol is photocatalyst 1, 2, 4 or 5; Preferably, the organic photocatalyst with a triplet energy >55 kcal / mol is photocatalyst 3 or a tricyclic organic photocatalyst; the tricyclic organic photocatalyst is preferably photocatalyst 6, 7 or 8; (13) The visible light source is a 6-watt blue LED lamp with a wavelength of 455-460nm.

4. The preparation method according to claim 3, characterized in that, It meets one or more of the following conditions: (1) When the photocatalyst is a complex of metallic iridium with a triplet energy >55kcal / mol, the wavelength of the visible light is 455nm±15nm, for example 455-460nm; Preferably, the iridium complex with triplet energy >55 kcal / mol is one or more of photocatalysts 1, 2, 4 and 5; (2) When the photocatalyst is a tricyclic organic photocatalyst with triplet energy >55kcal / mol, the wavelength of the visible light is 375±20nm, for example 385-390nm; Preferably, the tricyclic organic photocatalyst with a triplet energy >55 kcal / mol is one or more of photocatalysts 6-8; (3) The organic photocatalyst with triplet energy >55kcal / mol is a tricyclic organic photocatalyst; the tricyclic organic photocatalyst contains two aromatic rings and one non-aromatic carbon heterocycle. Preferably, the tricyclic organic photocatalyst has an aromatic ring-non-aromatic carbon heterocycle-aromatic ring framework structure; Preferably, the aromatic ring is C 6-12 Aromatic rings, such as benzene rings; Preferably, the aromatic ring is optionally substituted with a substituent, which is preferably a halogen or alkyl group; Preferably, the heteroatom in the non-aromatic carbon heterocycle is O or S; Preferably, the non-aromatic carbon heterocycle is a non-aromatic carbon heterocycle substituted with a carbonyl group; More preferably, the non-aromatic carbon heterocycle is More preferably, the tricyclic organic photocatalyst is (4) When the organic photocatalyst with triplet energy > 55 kcal / mol is photocatalyst 3. The wavelength of the visible light is 455nm ± 15nm, for example, 455-460nm.

5. The preparation method according to claim 1, characterized in that, The structure of the conjugated diene compound I is shown in formula I-1 or formula I-2: Among them, R 1 for -O-, -S-, -S(=O)2- or -N(R) 1c )-; R 1a and R 1b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH, -OC 1-6 Alkyl or halogen; R 1c Amino protecting group, H, C 1-6 Alkyl or C 6-14 Aryl; n is any integer greater than or equal to 0; R 2 H, halogen, C 1-6 Alkyl, C 6-14 Aryl, C 3-12 cycloalkyl, -OR 2c -OC(=O)-R 2d -C(=O)-R 2e -C(R) 2f R 2g R 2h -SC(=O)-C 1-6 Alkyl, -OS(=O)-C 6-14 Aryl, -SO2-C 6-14 aryl, 5-12 heteroaryl, 5-12 heteroaryl substituted with one or more carbonyl groups, or C substituted with one or more halogens. 1-6 alkyl; R 2a and R 2b Independently protected by amino, H, C 1-6 Alkyl, C 6-14 Aryl, OH, -OC 1-6 Alkyl or -C(=O)-R 2aa ; R 2aa C 1-6 Alkyl groups or C atoms substituted with one or more halogens 1-6 alkyl; R 2c For H, C 1-6 Alkyl, C 6-14 Aryl, hydroxyl protecting group, C 2-8 alkenyl or C 2-8 alkynyl group; R 2d For H, C 1-6 Alkyl, C 6-14 Aryl, C 3-12 cycloalkyl, C 2-8 alkenyl, C 2-8 alkynyl group, -C 1-6 Alkylene-R 2da , C replaced by one or more halogens 1-6 Alkyl groups or C groups substituted with one or more carbonyl groups 3-12 Cycloalkyl; R 2da CN, -C (=O) -C 1-6 alkyl, by one or more R 2daa Replacement C 6-14 aryl or aryl with one or more R 2dab Replacement C 3-12 Cycloalkyl; R 2daa Independently for -OC 1-6 Alkyl or C 1-6 alkyl; R 2dab Independently for C 1-6 Alkyl, OH or -OC 1-6 alkyl; R 2e For H, OH, C 1-6 Alkyl or -OC 1-6 alkyl; R 2f R 2g and R 2h Independently for C 1-6 Alkyl or -COO-C 1-6 alkyl; R 3 for -O-, -S-, -S(=O)2- or -N(R) 3c )-; R 3a and R 3b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl; R 3c It is an amino protecting group; R 4 for -O-, -S-, -S(=O)2- or -N(R) 4c )-; R 4a and R 4b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl; R 4c It is an amino protecting group.

6. The preparation method according to claim 5, characterized in that, It meets one or more of the following conditions: (1)R 1a and R 1b Independently for H and C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 alkyl; Preferably, R 1a For H; Preferably, R 1b For H, C 1-6 Alkyl, C 6-14 Aryl, OH or -OC 1-6 Alkyl, R 1b Preferably, it is H, methyl, ethyl, tert-butyl, phenyl, OH, or -O-CH3; (2)R 1 In the middle, the said for (3)R 1c It is an amino protecting group; Preferably, R 1c It can be p-toluenesulfonyl, tert-butoxycarbonyl, acetyl, benzoyl, benzyloxycarbonyl, p-bromobenzenesulfonyl, or methanesulfonyl; (4)R 1c R 2a R 2b R 3c and R 4c In this context, the amino protecting group is preferably a sulfonyl amino protecting group, an acyl amino protecting group, or a carbonate amino protecting group; The sulfonyl amino protecting group is preferably methanesulfonyl, trifluoromethanesulfonyl, p-methylbenzenesulfonyl, benzenesulfonyl, p-fluorobenzenesulfonyl, or p-bromobenzenesulfonyl; The acyl amino protecting group is preferably benzoyl, acetyl, trifluoroacetyl, or pivaloyl; The preferred amino protecting group of the carbonate is 9-fluorenylmethylcarbonyl, 2,2,2-trichloroethoxycarbonyl, tert-butoxycarbonyl, benzyloxycarbonyl or allyloxycarbonyl; (5) The -N(R) 1c )-for (6) n is any integer ≥ 0 and ≤ 10; Preferably, n is any integer ≥0 and ≤5, such as 0, 1, 2, 3, 4 or 5; (7)R 2 In this context, the 5-12 membered heteroaryl group substituted with one or more carbonyl groups is... (8)R 2c In this context, the hydroxyl protecting group is a sulfonyl hydroxyl protecting group, an acyl hydroxyl protecting group, a carbonate hydroxyl protecting group, an acetal hydroxyl protecting group, or a silyl ether hydroxyl protecting group; The sulfonyl hydroxyl protecting group is preferably methanesulfonyl, trifluoromethanesulfonyl, p-methylbenzenesulfonyl, benzenesulfonyl, p-fluorobenzenesulfonyl, or p-bromobenzenesulfonyl; The acyl hydroxyl protecting group is preferably benzoyl, acetyl, trifluoroacetyl, or pivaloyl; The carbonate hydroxyl protecting group is preferably 9-fluorenylmethylcarbonyl, 2,2,2-trichloroethoxycarbonyl, tert-butoxycarbonyl, benzyloxycarbonyl or allyloxycarbonyl; The acetal hydroxy protecting group is preferably methoxymethyl ether or 2-tetrahydropyran; The hydroxyl protecting group of the silyl ether is preferably trimethylsilyl ether, tert-butyldimethylsilyl ether or tert-butyldiphenylsilyl ether; Preferably, R 2c In this context, the hydroxyl protecting group is benzoyl or p-methylbenzenesulfonyl; (9)R 2d In, the C 1-6 Alkyl groups are -CH2-, -CH2-CH2-, Or -CH2-CH2-CH2-.

7. The preparation method according to claim 6, characterized in that, It satisfies one or more of the following conditions: (1) R 1 It can be any of the following structures: (2)R 2 It can be any of the following structures: (3)R 3 It can be any of the following structures: (4)R 4 It can be any of the following structures:

8. The preparation method according to claim 1, characterized in that, The structure of the cyclobutene compound II is shown in formula II-1 or II-2: Among them, R 1 R 2 n, R 3 and R 4 The definition is as described in any one of claims 5-7.

9. The preparation method according to claim 8, characterized in that, The structure of formula II-2 is shown in formula II-2a: Among them, R 3 and R 4 The definition is as described in any one of claims 5-7.

10. The preparation method according to claim 1, characterized in that, The conjugated diene compound I and the corresponding cyclobutene compound II have either of the following structures:

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