Method for synthesizing benzothiophene coupling product by non-metal participated anchoring-migration strategy

Abstract

The invention relates to the technical field of organic chemistry, in particular to a method for synthesizing a benzothiophene coupling product through a non-metal-participated anchoring-migration strategy. The method comprises the following steps: taking a benzothiophene compound or a benzothiophene sulfoxide compound as a reaction substrate, mixing the reaction substrate with an aryl nucleophilic reagent in the presence of an anhydride activator and a solvent, and carrying out nucleophilic substitution reaction to obtain benzothiophene sulfonium salt; the preparation method comprises the following steps: mixing benzothiophene sulfonium salt with an organic solvent, and carrying out metal-catalysis-free intramolecular migration reaction to form a carbon-carbon bond at the C2 site of benzothiophene, thereby obtaining the benzothiophene coupling product. The preparation conditions are mild, the operation is simple and convenient, a traditional oxidation addition-reduction elimination process is replaced by an anchoring-migration strategy, protection of a noble metal catalyst, a complex ligand, strong base or inert gas is not needed, and the problems of high cost, metal residues, harsh reaction conditions and limited substrate applicability in the prior art are fundamentally solved.

Description

Technical Field

[0001] This invention relates to the field of organic chemistry, and more specifically to a method for synthesizing benzothiophene coupling products using a non-metallic "anchoring-migration" strategy. Background Technology

[0002] Benzothiophenes are an important core scaffold for drugs, widely found in pharmacologically active organic molecules. Although their derivatives exhibit diverse biological activities, the number of successfully marketed drugs based on the benzothiophene scaffold is significantly fewer compared to its structural analogue, indole. This is because benzothiophenes are chemically more inert than indole, thus posing a significant challenge to the efficient construction of complex molecular libraries using them as basic building blocks.

[0003] Currently, the direct modification of benzothiophene mainly relies on transition metal catalytic systems, achieving cross-coupling with halogenated aromatic hydrocarbons through inert C-H bond activation. Taking C2-position arylation as an example, typical conditions involve using aryl bromide as the coupling agent, in a system catalyzed by palladium / substituted 1,10-phenanthroline complex (DPP-NNC Pd), with potassium carbonate as the base and tert-amyl alcohol as the additive, reacting at 150°C for 20 hours in dimethylacetamide solvent, to introduce the aromatic ring into the C2 position of benzothiophene. Similarly, by changing the catalytic conditions, the aromatic ring can also be selectively modified at the C3 position of benzothiophene. For example, using aryl iodine as the coupling target, Pd2(dba)3·CHCl3 as the catalyst, silver carbonate as the additive, and hexafluoroisopropanol as the solvent, a reaction of 16 hours can yield C3-arylated benzothiophene derivatives with high selectivity. However, this type of method requires the use of expensive palladium metal and ligands, and relies on bases or other additives. It suffers from problems such as high cost of catalysts and ligands, metal residues, harsh reaction conditions, limited substrate applicability, and poor selectivity, which seriously restrict the large-scale synthesis and development of benzothiophene drugs.

[0004] In addition, existing studies have reported a method for arylizing benzothiophene at the C2 and C3 positions through interrupted pummerer reaction and [3,3]-migration strategy. However, the substrates for this method are mainly limited to the arylization of phenols and enyne compounds, which restricts its application. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy. This invention offers a novel method for the C2-position arylation of benzothiophene, using benzothiophene compounds or benzothiophene sulfoxide compounds as substrates. These compounds undergo a nucleophilic substitution reaction with an aryl nucleophile in the presence of an anhydride activator to obtain a benzothiophene sulfonate. Subsequently, the benzothiophene sulfonate is mixed with an organic solvent, and selective arylation of the C2 position of benzothiophene is achieved through a metal-free intramolecular migration reaction to obtain the benzothiophene coupling product. The preparation conditions of this invention are mild and the operation is simple. It replaces the traditional "oxidative addition-reductive elimination" process with an "anchor-migration" strategy and eliminates the need for precious metal catalysts, complex ligands, strong bases, or inert gas protection. This fundamentally solves the problems of high cost, metal residue, harsh reaction conditions, and limited substrate applicability associated with existing technologies, providing a green, efficient, and economical preparation route for constructing benzothiophene molecular libraries.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy, comprising the following steps: S1. Using benzothiophene compounds or benzothiophene sulfoxide compounds as reaction substrates, the reaction substrates are mixed with aryl nucleophiles in the presence of an anhydride activator and solvent, and a nucleophilic substitution reaction is carried out to obtain benzothiophene sulfonate. During the nucleophilic substitution reaction, the SO bond of the benzothiophene sulfoxide compound is highly polar, and the oxygen atom readily donates electrons, enhancing the electrodeficient nature of the sulfur atom. This invention uses an electron-deficient anhydride to capture electrons from the oxygen atom, causing the SO bond to break and generating the activated form of benzothiophene. After activation, the electrophilicity of the sulfur atom is significantly enhanced, and the nucleophile can transfer its electrons to the sulfur atom, forming a new covalent bond with the sulfur atom through the nucleophilic substitution reaction, thus achieving anchoring between the two molecules.

[0007] S2. The benzothiophene sulfonate salt is mixed with an organic solvent and subjected to a metal-free intramolecular migration reaction to form a carbon-carbon bond at the C2 position of benzothiophene, thus obtaining the benzothiophene coupling product.

[0008] The technical approach of this invention is as follows: When the aryl nucleophile is a 4-hydroxycoumarin compound, the technical route is as follows: .

[0009] When the aryl nucleophile is selected from 1,3-cyclopentanedione, 1,3-cyclohexanedione, thiophene, toluene, anisole, piperonyl ring, or mesitylene, the technical route is as follows: .

[0010] Preferably, the solvent in S1 is selected from at least one of dichloromethane, 1,2-dichloroethane, and acetonitrile.

[0011] Preferably, the acid anhydride activator is selected from trifluoroacetic anhydride or trifluoromethanesulfonic anhydride.

[0012] Preferably, the organic solvent in S2 is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, toluene, and acetonitrile.

[0013] Preferably, the nucleophilic substitution reaction conditions are: stirring at -40°C or -78°C for 0.5 h to 1 h. According to literature methods, when using trifluoroacetic anhydride, the reaction is generally initiated at -40°C, then moved to room temperature and stirred for 0.5 h; when using trifluoromethanesulfonic anhydride, the reaction is initiated at -78°C, then moved to room temperature and stirred for 1 h.

[0014] A second objective of this invention is to provide a benzothiophene coupling product obtained by the above preparation method.

[0015] A third objective of this invention is to provide a polycyclic aromatic hydrocarbon compound prepared by photocyclization reaction of the above-mentioned benzothiophene coupling product.

[0016] Preferably, the photocyclization reaction is carried out under the following conditions: at room temperature, under light with a wavelength of 365nm~455nm and an intensity of 15W for 2h~6h.

[0017] Preferably, the cyclization reaction takes place in an air atmosphere or an argon atmosphere; more preferably, the cyclization reaction takes place in an argon atmosphere.

[0018] Preferably, the solvent for the cyclization reaction is selected from acetonitrile, toluene, ethyl acetate, dichloromethane, tetrahydrofuran, DMF, DMSO or NMP.

[0019] A fourth objective of this invention is to provide the application of the aforementioned polycyclic aromatic hydrocarbons in the preparation of optoelectronic materials.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy. Using benzothiophene compounds or benzothiophene sulfoxide compounds as reaction substrates, the reaction substrates are mixed with an aryl nucleophile in the presence of an anhydride activator and solvent, and a nucleophilic substitution reaction is carried out to obtain benzothiophene sulfonium salts. The benzothiophene sulfonium salts are then mixed with an organic solvent, and a metal-free intramolecular migration reaction is carried out. After the carbon-hydrogen bond at the C2 position of the benzothiophene sulfonium salt is polarized, the α-carbon fragment of the aryl nucleophile migrates from the sulfur atom to the C2 position, while CS... +The bond breaks, and a new C-C bond is eventually formed at the C2 position of the benzothiophene sulfonate to obtain the benzothiophene coupling product; the intramolecular migration reaction is carried out under the following conditions: stirring at 90℃~150℃ for 3h~24h.

[0021] Compared to traditional coupling strategies, this invention uses a simple "anchor-migration" strategy to synthesize benzothiophene coupling products, avoiding the traditional "oxidative addition-reductive elimination" process. The reaction process of this invention does not require transition metals and ligands, nor does it require pre-activation of the coupling target, which significantly reduces the preparation cost of various types of benzothiophene derivatives, simplifies the synthesis steps, eliminates the problem of metal residues, and enables the green, efficient and low-cost preparation of more types of benzothiophene molecules.

[0022] 2. The benzothiophene coupling product of the present invention is a new compound molecule in which benzothiophene is linked to other aromatic nucleophiles or drug-dominant backbone molecules (such as coumarin and antipyrine) through a C2-C2 bond, and has potential drug activity.

[0023] 3. Based on the benzothiophene coupling product, this invention further constructs a polycyclic heteroaromatic compound with both benzothiophene and coumarin dual skeletons through a one-pot tandem reaction. This process utilizes the intramolecular cyclization of the C3 aryl group and C2 coumarin structure of the benzothiophene coupling product to efficiently form a rigid planar polycyclic conjugated structure. These polycyclic heteroaromatic compounds not only retain the pharmacological activity potential of the benzothiophene skeleton but also possess excellent photoelectric properties due to the extended conjugated system, demonstrating dual application value in the fields of organic light-emitting diodes, fluorescence sensing, and the development of antitumor drug lead compounds. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that the technical terms used in this invention are only for describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased commercially or prepared by existing methods. Unless otherwise specified, the raw materials, solvents, etc., used in the experiments are commercially available chemical raw materials and chemical reagents. Among them, trifluoroacetic anhydride is denoted as TFAA; the reaction substrates in this invention include benzothiophene compounds or benzothiophene sulfoxide compounds, wherein benzothiophene compounds 1a, 1d, 1i, 1j, and 1k are commercially purchased, and the commercial reagents used are used directly without further purification; 1b, 1c, 1e, 1f, 1g, and 1h are prepared according to the literature " Angew. Chem. Int. Ed. The compounds were prepared from "2022, e202203908", and all of them are known compounds.

[0026] .

[0027] Benzothiophene sulfoxide compounds are referenced from " J. Org. Chem. 1997, 62 "7926-7936", and obtained through in-situ oxidation, the technical route is as follows: This includes the following steps: Benzothiophene (1.0 equivalent) and BF3·Et2O (8.0 equivalent) were dissolved together in CH2Cl2 (0.1 mol / L) under N2 protection to obtain a reaction solution; the oxidant was then added at -20℃. m -CPBA (1.02 equivalents) dissolved in a small amount of CH2Cl2 to give m -CPBA solution; m -CPBA solution was added dropwise to the reaction solution in three batches, with each batch 30 min apart, to obtain a mixture. After the reaction solution was completely consumed by TLC, the mixture was quenched and neutralized successively with saturated K2CO3 solution and solid K2CO3 at -20℃. Then, it was filtered through a double-layer filter of anhydrous Na2SO4 and K2CO3, and the filter cake was washed with CH2Cl2. The resulting filtrate was the benzothiophene sulfoxide solution.

[0028] For benzothiophene sulfoxide compounds without substitution at both C2 and C3 positions, the resulting filtrate is unstable during post-treatment concentration. Therefore, it is used directly as a starting material for the next reaction, such as the method in the examples for preparing benzothiophene coupling products using 1a, 1b, 1c, 1d, and 1e as reaction substrates.

[0029] For benzothiophene sulfoxide compounds with substituents at the C2 or C3 positions, the resulting filtrate can be concentrated under reduced pressure to remove most of the CH2Cl2. Therefore, a small amount of petroleum ether is added to the filtrate, and after the solid precipitates, it is filtered and washed with petroleum ether to obtain benzothiophene sulfoxide compounds, such as 2a, 2c, 2d, 2j, 2k, and 2l.

[0030] The compounds benzothiophene sulfoxide 2b, 2e, 2f, 2g, 2h, 2i, and 2m all start from 2k. (References) Cheminform , 2015, 46 (5901-5905), obtained through Suzuki coupling, as follows: ①3-p-methylphenylbenzo[ b The preparation method of thiophene sulfoxide (2b) is as follows: This includes the following steps: 2 kJ of 3-bromobenzothiophene sulfoxide (458.2 mg, 2.0 mmol, 1.0 equivalent) and p-methylphenylboronic acid (326.4 mg, 2.4 mmol, 1.2 equivalent) were dissolved in 15 mL of THF solution. K₂CO₃ (1.725 g, 12.5 mmol, 6.25 equivalent), H₂O (6.25 mL), and tetrakis(triphenylphosphine)palladium (115.6 mg, 5 mol%) were added sequentially. The reaction was carried out at 70 °C for 12 h under argon protection. After the reaction was complete as monitored by TLC, the reaction solution was extracted three times with EA / H₂O. The organic phase was collected, dried over anhydrous sodium sulfate, and then the solvent was removed under reduced pressure to obtain the crude product. The crude product was purified by column chromatography to obtain 3-p-methylphenylbenzo[ b Thiophene sulfoxide (2b), yellow solid 430.8 mg, yield 82%, melting point: 42.8℃~43.5℃.

[0031] 1 H NMR (400 MHz, Chloroform- d ) δ 8.01 – 7.96 (m, 1H), 7.60 – 7.50 (m,3H), 7.45 (d, J = 8.0 Hz, 2H), 7.31 (d, J = 8.0 Hz, 2H), 6.96 (s, 1H), 2.44 (s, 3H). 13 C NMR (101 MHz, Chloroform- d) δ 148.68, 146.74, 140.31, 137.53, 132.12,131.84, 129.87 (2C), 129.78, 129.08, 128.11 (2C), 126.76, 124.60, 21.55. HRMS(ESI) calcd. for C 15 H 13 OS + (M+H + ) 241.0682, found 241.0686.

[0032] ②3-(3-nitrophenyl)benzo[ b The preparation method of thiophene sulfoxide (2e) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 3-nitrophenylboronic acid to obtain 3-(3-nitrophenyl)benzo[ b Thiophene sulfoxide (2e), grayish-white solid, yield 95%, melting point: 181.8℃~183.4℃.

[0033] 1 H NMR (400 MHz, Chloroform- d ) δ 8.42 (t, J = 2.0 Hz, 1H), 8.37 (ddd, J =7.6, 2.4, 1.2 Hz, 1H), 8.05 – 8.00 (m, 1H), 7.89 (ddd, J = 7.6, 1.6, 1.2 Hz,1H), 7.74 (t, J = 8.0 Hz, 1H), 7.62 – 7.56 (m, 2H), 7.52 – 7.46 (m, 1H), 7.15(s, 1H). 13 C NMR (101 MHz, Chloroform- d ) δ 148.65, 146.42, 145.94, 136.33,134.85, 134.19, 133.97, 132.16, 130.38, 129.58, 127.06, 124.63, 123.91,123.01. HRMS (ESI) calcd. for C 14 H 10 NO3S + (M+H +) 272.0376, found 272.0374.

[0034] ③The preparation method of methyl 2-(1-benzo[b]thiophene-3-yl)benzoate (2f) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 3-(methoxycarbonyl)phenylboronic acid to obtain methyl 2-(1-benzo[b]thiophene-3-yl)benzoate (2f), a white solid with a yield of 42% and a melting point of 69.7℃~71.3℃.

[0035] 1 H NMR (600 MHz, Chloroform- d ) δ 8.10 (dd, J = 7.8, 1.2 Hz, 1H), 7.97(d, J = 7.8 Hz, 1H), 7.66 (td, J = 7.8, 1.2 Hz, 1H), 7.58 (td, J = 7.8, 1.2 Hz,1H), 7.49 – 7.42 (m, 3H), 7.01 (d, J = 7.8 Hz, 1H), 6.91 (s, 1H), 3.60 (s, 3H). 13 C NMR (101 MHz, Chloroform- d ) δ 166.66, 149.17, 145.46, 138.75, 135.65,132.97, 132.48, 131.85, 130.96, 130.49, 130.44, 129.64, 128.78, 126.30,123.53, 52.26. HRMS (ESI) calcd. for C 16 H 13 O3S + (M+H + ) 285.0580, found 285.0585. ④ The preparation method of 2-(1-benzo[b]thiophene-3-yl)benzonitrile (2g) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 4-cyano-2-(4,4,5,5-tetramethyl-1,3,2-dioxoborane heterocyclic)benzene to obtain 2-(1-benzo[b]thiophene-3-yl)benzonitrile (2g), a white solid with a yield of 87% and a melting point of 180.2℃~182.6℃.

[0036] 1 H NMR (600 MHz, Chloroform- d ) δ 8.07 – 8.03 (m, 1H), 7.88 (d, J = 7.8Hz, 1H), 7.79 (t, J = 7.8 Hz, 1H), 7.67 – 7.62 (m, 2H), 7.61 – 7.55 (m, 3H), 7.32 – 7.28 (m, 1H). 13 C NMR (151 MHz, Chloroform- d ) δ 146.8, 144.23, 136.85,136.70, 135.83, 134.12, 133.28, 132.12, 130.08, 129.86, 129.60, 126.95,124.29, 117.12, 112.00. HRMS (ESI) calcd. for C 15 H9NNaOS + (M+Na + ) 274.0297, found 274.0302. ⑤3-(3-methoxyphenyl)benzo[ b The preparation method of thiophene sulfoxide (2h) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 3-methoxyphenylboronic acid to obtain 3-(3-methoxyphenyl)benzo[ b Thiophene sulfoxide (2h), white solid, yield 85%, melting point: 74.5℃~76.8℃.

[0037] 1 H NMR (400 MHz, Chloroform- d ) δ 8.01 – 7.97 (m, 1H), 7.60 – 7.50 (m,3H), 7.43 (t, J= 8.0 Hz, 1H), 7.15 – 7.11 (m, 1H), 7.08 – 7.02 (m, 2H), 7.00 (s, 1H), 3.87 (s, 3H). 13 C NMR (101 MHz, Chloroform- d ) δ 160.09, 148.58,146.61, 137.37, 133.92, 132.75, 131.93, 130.30, 129.20, 126.78, 124.62,120.48, 115.49, 113.80, 55.56. HRMS (ESI) calcd. for C 15 H 13 O2S + (M+H + ) 257.0631, found 257.0629. ⑥3-(1-methyl-1 H -pyrazole-5-yl)benzo[ b The preparation method of thiophene sulfoxide (2i) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 1-(4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-yl)-1H-pyrazole to obtain 3-(1-methyl-1 H -pyrazole-5-yl)benzo[ b Thiophene sulfoxide (2i), white solid, yield 87%, melting point 129.3℃~132.9℃.

[0038] 1 H NMR (600 MHz, Chloroform- d ) δ 8.02 – 7.99 (m, 1H), 7.63 (d, J = 1.8Hz, 1H), 7.60 – 7.55 (m, 2H), 7.51 – 7.48(m, 1H), 7.08 (s, 1H), 6.54 (d, J =1.8 Hz, 1H), 3.95 (s, 3H). 13 C NMR (101 MHz, Chloroform- d) δ 145.62, 139.15,137.06, 136.72, 135.10, 133.74, 132.19, 129.60, 126.71, 124.38, 108.15,37.94. HRMS (ESI) calcd. for C 12 H 10 N2NaOS + (M+Na + ) 253.0406, found 253.0405. ⑦3-(2-chloropyridin-3-yl)benzo[ b The preparation method of thiophene sulfoxide (2m) is as follows: The preparation method is the same as that of 2b, except that p-methylphenylboronic acid is replaced with 6-chloro-3-pyridine-phenylboronic acid to obtain 3-(2-chloropyridin-3-yl)benzo[ b Thiophene sulfoxide (2m), white solid, yield 83%, melting point: 145.5℃~147.8℃.

[0039] 1 H NMR (600 MHz, Chloroform- d ) δ 8.54 (dd, J = 4.8, 1.8 Hz, 1H), 8.01 –7.99 (m, 1H), 7.76 (dd, J = 7.2, 1.8 Hz, 1H), 7.55 – 7.50 (m, 2H), 7.41 (dd, J =7.2, 4.8 Hz, 1H), 7.18 (dd, J = 7.2, 1.8 Hz, 1H), 7.12 (s, 1H). 13 C NMR (151 MHz, Chloroform- d ) δ 150.66, 149.73, 145.77, 143.98, 139.49, 136.78, 136.50,132.06, 129.44, 128.44, 126.67, 124.45, 122.75. HRMS (ESI) calcd. forC 13 H8ClNNaOS + (M+Na + ) 283.9907, found 283.9914. The benzothiophene coupling products in the following examples were all prepared using the above-mentioned benzothiophene compound or benzothiophene sulfoxide compound as the reaction substrate.

[0040] Examples 1 to 32 describe the preparation of benzothiophene coupling products by using 4-hydroxycoumarin compounds as nucleophiles, under anhydride activation conditions, to "anchor" them to the benzothiophene structure, followed by a metal-free "migration" process.

[0041] Example 1 A method for synthesizing benzothiophene coupling products using a non-metallic "anchoring-migration" strategy, the technical route of which is as follows: This includes the following steps: 3-Phenylacetyl sulfoxide 2a (0.1 mmol, 22.6 mg, 1.0 equivalent) was dissolved in 1 mL of DCM (0.1 mol / L). The anhydride was activated by adding TFAA (0.3 mmol, 42 μL, 3.0 equivalent) at -40 °C. After 10 min, 4-hydroxycoumarin (0.11 mmol, 17.8 mg, 1.1 equivalent) was added, and the mixture was stirred for 10 min before being allowed to react at room temperature for 0.5 h. The DCM was removed by concentration under reduced pressure, and 1 mL of DMF was added. The mixture was stirred at 130 °C for 3 h. After the reaction was complete as detected by TLC, the reaction solution was extracted with H2O (20 mL) and EA (10 mL × 3), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by preparative thin-layer chromatography to obtain compound 5, namely 4-hydroxy-3-(3-phenylbenzo[ b Thiophene-2-yl)coumarin, yellow solid, yield 74%, melting point: 188.7℃~189.5℃.

[0042] 1 H NMR (600 MHz, DMSO- d 6) δ 8.06 (d, J = 7.8 Hz, 1H), 7.84 (d, J = 8.4 Hz, 1H), 7.65 (t, J = 8.4 Hz, 1H), 7.59 (d, J = 7.8 Hz, 1H), 7.47 – 7.28 (m, 9H). 13 CNMR (101 MHz, DMSO- d6) δ 164.11, 161.72, 153.17, 140.45, 139.69, 138.24,135.13, 133.48, 129.34 (2C), 128.93 (2C), 128.03, 125.27, 124.91, 124.61,124.40, 123.25, 123.07, 116.83, 116.17, 98.27. HRMS (ESI) calcd. forC 23 H 14 NaO3S + (M+Na + ) 393.0556, found 393.0573. Example 2 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-p-methylphenylbenzothiophene sulfoxide 2b (0.1 mmol, 24.0 mg, 1.0 equivalent), yielding compound 6, namely 4-hydroxy-3-(3-(p-methyl)phenylbenzo[ b Thiophene-2-yl)coumarin, a yellow solid, 68% yield, melting point: 122.4℃~123.8℃, its structural formula is... .

[0043] HRMS (ESI) calcd. for C 24 H 16 NaO3S + (M+Na + ) 407.0712, found 407.0719. Example 3 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-p-fluorophenylbenzothiophene sulfoxide 2c (0.1 mmol, 24.0 mg, 1.0 equivalent), yielding compound 7, namely 3-(3-(4-fluorophenyl)benzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow oily liquid with a yield of 86%, has the following structural formula: .

[0044] HRMS (ESI) calcd. for C 23 H 13 FNaO3S + (M+Na + ) 411.0462, found 411.0473. Example 4 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-p-nitrophenylbenzothiophene sulfoxide 2d (0.1 mmol, 27.1 mg, 1.0 equivalent), yielding compound 8, namely 3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow solid, 89% yield, melting point 204.4℃~206.3℃, has the following structural formula: .

[0045] 1 H NMR (400 MHz, DMSO- d 6) δ 8.26 (d, J = 8.8 Hz, 2H), 8.05 (dd, J = 7.2, 2.0 Hz, 1H), 7.81 (dd, J = 8.0, 1.6 Hz, 1H), 7.69 – 7.55 (m, 4H), 7.47 – 7.39(m, 2H), 7.33 – 7.24 (m, 2H). 13 C NMR (151 MHz, DMSO- d 6) δ 161.85, 153.50,146.86, 142.93, 140.31, 138.93, 134.93, 132.93, 130.64 (2C), 125.18, 125.03,124.73, 124.14 (2C), 124.06, 123.04, 122.56, 118.02, 116.66, 115.96, 96.03.HRMS (ESI) calcd. for C 23 H 13 NaO5S + (M+Na + ) 438.0407, found 438.0414. Example 5 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-(3-nitrophenyl)benzothiophene sulfoxide 2e (0.1 mmol, 27.1 mg, 1.0 equivalent), yielding compound 9, namely 3-(3-(3-nitrophenyl)benzo[ bThiophene-2-yl)-4-hydroxycoumarin, a yellow solid, yield 82%, melting point >300℃, its structural formula is: .

[0046] HRMS (ESI) calcd. for C 23 H 13 NaO5S + (M+Na + ) 438.0407, found 438.0417.

[0047] Example 6 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with methyl 2-(1-oxobenzo[b]thiophene-3-yl)benzoate 2f (0.1 mmol, 28.4 mg, 1.0 equivalent), yielding compound 10, namely methyl 2-(2-(4-hydroxycoumarinyl)benzo[b]thiophene-3-yl)benzoate, a yellow solid with a yield of 47% and a melting point of 205.3-206.7 °C. Its structural formula is as follows: .

[0048] HRMS (ESI) calcd. for C 25 H 16 NaO5S + (M+Na + ) 451.0611, found 451.0617. Example 7 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 2g of methyl 2-(1-oxobenzo[b]thiophene-3-yl)benzoate (0.1 mmol, 25.1 mg, 1.0 equivalent), yielding compound 11, namely methyl 2-(2-(4-hydroxycoumarinyl)benzo[b]thiophene-3-yl)benzoate, a yellow solid with a yield of 91% and a melting point of 168.7℃~169.9℃. Its structural formula is as follows: .

[0049] HRMS (ESI) calcd. for C 24 H 13 NNaO3S + (M+Na + ) 418.0508, found 418.0507. Example 8 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-(3-methoxyphenyl)benzo[ b Thiophene sulfoxide was subjected to reactants for 2 hours (0.1 mmol, 25.6 mg, 1.0 equivalent) to yield compound 12, namely 3-(3-(3-methoxyphenyl)benzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow solid, 56% yield, melting point: 102.8℃~104.7℃, its structural formula is... .

[0050] HRMS (ESI) calcd. for C 24 H 16 NaO4S + (M+Na + ) 423.0662, found 423.0687.

[0051] Example 9 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 1, except that 2a is replaced with 3-(1-methyl-1-yl)-methyl-2-yl ... H -pyrazole-5-yl)benzo[ b Thiophene sulfoxide 2i (0.1 mmol, 23.0 mg, 1.0 equivalent) yielded compound 13, namely 3-(3-(1-methyl-1-ethylhexylene) H -pyrazole-5-yl)benzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow solid, 68% yield, melting point: 275.4℃~278.3℃, its structural formula is... .

[0052] HRMS (ESI) calcd. for C 21 H 14 N2NaO3S + (M+Na + ) 397.0617, found 397.0623.

[0053] Example 10 A method for synthesizing benzothiophene coupling products using a non-metallic "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with 3-methylbenzo[ b Thiophene sulfoxide 2j (0.1 mmol, 16.4 mg, 1.0 equivalent) yielded compound 14, namely 3-(3-methylbenzo[ bThiophene-2-yl)-4-hydroxycoumarin, a yellow-green solid, 40% yield, melting point: 181.0℃~183.2℃, its structural formula is... .

[0054] HRMS (ESI) calcd. for C 18 H 12 NaO3S + (M+Na + ) 331.0399, found 331.0393. Example 11 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 1, except that 2a is replaced with 3-bromobenzo[ b Thiophene sulfoxide 2kJ (0.1 mmol, 22.9 mg, 1.0 equivalent) yielded compound 15, namely 3-(3-bromobenzo[...] b Thiophene-2-yl)-4-hydroxycoumarin, a pale red solid, yield 20%, melting point: 234.8℃~235.5℃, its structural formula is... .

[0055] HRMS (ESI) calcd. for C 17 H9BrNaO3S + (M+Na + ) 394.9348, found 394.9354. Example 12 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 1, except that 2a is replaced with 5-bromo-3-methylbenzo[ b Thiophene sulfoxide 2l (0.1 mmol, 19.9 mg, 1.0 equivalent) yielded compound 16, namely 3-(5-bromo-3-methylbenzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow solid, yield 65%, melting point >300℃, its structural formula is .

[0056] HRMS (ESI) calcd. for C 18 H 11 ClNaO3S + (M+Na + ) 365.0010, found 365.0011. Example 13 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 1, except that 2a is replaced with 3-(2-chloropyridin-3-yl)benzo[ b Thiophene sulfoxide 2m (0.1mmol, 26.2mg, 1.0 equivalent), the technical route is as follows: , Compound 17 was not observed in the reaction, but compound 18 (CCDC: 2489701) was further generated by recrystallization in a mixed solvent of petroleum ether and acetone. It was a yellow solid with a yield of 81% and a melting point of 166.3℃~167.6℃.

[0057] 1 H NMR (600 MHz, Chloroform- d ) δ 8.56 (dd, J = 7.8, 1.2 Hz, 1H), 8.43(dd, J = 4.8, 1.8 Hz, 1H), 8.23 ​​(dd, J = 7.8, 1.8 Hz, 1H), 8.00 – 7.97 (m, 2H), 7.66 – 7.64 (m, 1H), 7.50 – 7.46 (m, 3H), 7.43 – 7.40 (m, 2H). 13 C NMR (101MHz, Chloroform- d ) δ 161.69, 161.18, 160.47, 153.03, 148.59, 141.46, 139.25,136.44, 133.29, 133.26, 130.80, 125.83, 125.79, 125.29, 125.10, 123.03,123.01, 122.89, 122.33, 117.23, 116.54, 111.49. HRMS (ESI) calcd. forC 22 H 11 NNaO3S + (M+Na + ) 392.0352, found 392.0359. Examples 14-18 used benzothiophene as a reaction substrate and oxidized it in situ to obtain a benzothiophene sulfoxide solution. The benzothiophene sulfoxide solution was then used to prepare benzothiophene coupling products directly in a one-pot process without separation and purification.

[0058] Example 14 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 1, except that 2a is replaced with a benzothiophene sulfoxide solution obtained by in-situ oxidation of 4-phenylbenzothiophene 1d (0.1 mmol, 21.0 mg, 1 equivalent), and the concentration of the benzothiophene sulfoxide solution is 0.1 mmol / L, yielding compound 19, namely 4-hydroxy-3-(4-phenylbenzo[ b Thiophene-2-yl)-coumarin, a brown solid, yield 67%, melting point: 226.2℃~227.5℃; its structural formula is... .

[0059] 1 H NMR (400 MHz, DMSO- d 6) δ 8.54 (s, 1H), 7.98 (dd, J = 8.0, 1.6 Hz, 1H), 7.81 (d, J = 6.8 Hz, 1H), 7.62 – 7.60 (m, 2H), 7.54 – 7.46 (m, 3H), 7.44 –7.40 (m, 1H), 7.25 – 7.19 (m, 4H). 13 C NMR (151 MHz, DMSO- d 6) δ 169.94, 162.43,152.99, 141.89, 140.77, 139.47, 137.87, 135.22, 131.42, 129.20 (2C), 129.03(2C), 127.45, 125.34, 124.20, 123.08, 122.42, 121.32, 120.88, 117.14, 116.16,96.26. HRMS (ESI) calcd. for C 23 H 14 NNaO3S + (M+Na + ) 393.0556, found 393.0556. Example 15 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 1d is replaced with 7-phenylbenzothiophene 1e (0.1 mmol, 21.0 mg, 1 equivalent), yielding compound 20, namely 4-hydroxy-3-(7-phenylbenzo[ bThiophene-2-yl)-coumarin, a pale yellow solid, 85% yield, melting point: 215.6℃~217.8℃, its structural formula is... .

[0060] HRMS (ESI) calcd. for C 23 H 14 NNaO3S + (M+Na + ) 393.0556, found 393.0556. Example 16 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 1d is replaced with 5-phenylbenzothiophene 1c (0.1 mmol, 21.0 mg, 1 equivalent), yielding compound 21, namely 4-hydroxy-3-(5-phenylbenzo[ b Thiophene-2-yl)-coumarin, a yellow solid, 29% yield, melting point: 234.9℃~236.1℃, its structural formula is... .

[0061] HRMS (ESI) calcd. for C 23 H 14 NNaO3S + (M+Na + ) 393.0556, found 393.0556. Example 17 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 1d is replaced with 7-methylbenzothiophene 1j (0.1 mmol, 14.8 mg, 1 equivalent), yielding compound 22, namely 4-hydroxy-3-(7-methylbenzo[ b Thiophene-2-yl)-coumarin, a yellow solid, yield 26%, melting point >300℃, its structural formula is: .

[0062] HRMS (ESI) calcd. for C 18 H 12 NaO3S + (M+Na + ) 331.0399, found 331.0401. Example 18 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 1d is replaced with benzothiophene 1a (0.1 mmol, 13.4 mg, 1 equivalent), yielding compound 23, namely 3-(benzo[ b Thiophene-2-yl)-4-hydroxycoumarin, a yellow solid, 55% yield, has the following structural formula: .

[0063] 1 H NMR (600 MHz, DMSO- d 6) δ 8.22 (d, J = 0.6 Hz, 1H), 8.14 (dd, J = 7.8, 1.2 Hz, 1H), 7.94 – 7.92 (m, 1H), 7.86 – 7.84 (m, 1H), 7.68 – 7.65 (m, 1H), 7.43 – 7.39 (m, 2H), 7.36 – 7.30 (m, 2H). Compound 23 is a known compound, and the experimental data are similar to those in the literature. Org. Lett. 2002, 4 , 3333–3336).

[0064] Example 19 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 4-hydroxy-5-methylcoumarin (0.11 mmol, 1.1 equivalents), yielding compound 24, namely 4-hydroxy-5-methyl-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, 74% yield, melting point: 154.7℃~157.0℃, its structural formula is... .

[0065] 1 H NMR (400 MHz, DMSO- d 6) δ 8.29 (d, J = 8.8 Hz, 2H), 8.10 – 8.08 (m,1H), 7.65 (d, J = 8.8 Hz, 2H), 7.63 – 7.61 (m, 1H), 7.51 – 7.42 (m, 3H), 7.18(d, J = 8.0 Hz, 1H), 7.10 (d, J= 7.6 Hz, 1H), 2.59 (s, 3H). 13 C NMR (151 MHz, DMSO- d 6) δ 167.44, 161.08, 154.64, 147.13, 142.31, 140.60, 139.15, 138.29,136.45, 132.61, 131.96, 130.72 (2C), 128.06, 125.55, 125.20, 124.23 (2C),123.19, 122.91, 115.23, 115.03, 97.42, 23.55. HRMS (ESI) calcd. forC 24 H 15 NNaO5S + (M+Na + ) 452.0563, found 452.0562. Example 20 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 5-chloro-4-hydroxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 25, namely 5-chloro-4-hydroxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, yellow solid, yield 63%, melting point: 176.8-178.0 ℃. Its structural formula is .

[0066] HRMS (ESI) calcd. for C 23 H 12 ClNNaO5S + (M+Na + ) 472.0017, found 472.0019. Example 21 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 4-hydroxy-6-methylcoumarin (0.11 mmol, 1.1 equivalents), yielding compound 26, namely 4-hydroxy-6-methyl-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, yield 61%, melting point >300℃, its structural formula is .

[0067] HRMS (ESI) calcd. for C 24 H 15 NNaO5S + (M+Na + ) 452.0563, found 452.0554. Example 22 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 4-hydroxy-6-methoxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 27, namely 4-hydroxy-6-methoxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, 78% yield, melting point: 155.6℃~158.4℃, its structural formula is... .

[0068] HRMS (ESI) calcd. for C 24 H 15 NNaO6S + (M+Na + ) 468.0512, found 468.0512. Example 23 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 6-chloro-4-hydroxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 28, namely 6-chloro-4-hydroxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, an orange-yellow solid, 74% yield, melting point: 238.5℃~240.7℃, its structural formula is... .

[0069] HRMS (ESI) calcd. for C 23 H 12 ClNNaO5S + (M+Na + ) 472.0017, found 472.0015.

[0070] Example 24 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 6-bromo-4-hydroxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 29, namely 6-bromo-4-hydroxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, an orange-yellow solid, 79% yield, melting point: 237.7℃~249.0℃, its structural formula is... .

[0071] HRMS (ESI) calcd. for C 23 H 12 BrNNaO5S + (M+Na + ) 515.9512, found 515.9515. Example 25 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 14, except that 4-hydroxycoumarin is replaced with 4-hydroxy-7-methylcoumarin (0.11 mmol, 1.1 equivalents), yielding compound 30, namely 4-hydroxy-7-methyl-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, 77% yield, melting point: 186.6℃~188.3℃, its structural formula is... .

[0072] HRMS (ESI) calcd. for C 24 H 15 NNaO5S + (M+Na + ) 452.0563, found 452.0576. Example 26 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxy-7-methoxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 31, namely 4-hydroxy-7-methoxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, 48% yield, melting point: 224.4℃~226.0℃, its structural formula is... .

[0073] HRMS (ESI) calcd. for C24 H 15 NNaO6S + (M+Na + ) 468.0512, found 468.0515. Example 27 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 7-bromo-4-hydroxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 32, namely 7-bromo-4-hydroxy-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a pale yellow solid, 88% yield, melting point: 209.9℃~212.1℃, its structural formula is... .

[0074] HRMS (ESI) calcd. for C 23 H 12 BrNNaO5S + (M+Na + ) 515.9512, found 515.9521. Example 28 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxy-8-methylcoumarin (0.11 mmol, 1.1 equivalents), yielding compound 33, namely 4-hydroxy-8-methyl-3-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-coumarin, a yellow solid, 84% yield, melting point: 157.7℃~161.5℃, its structural formula is: .

[0075] HRMS (ESI) calcd. for C 24 H 15 NNaO5S + (M+Na + ) 452.0563, found 452.0569. Example 29 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 8-bromo-4-hydroxycoumarin (0.11 mmol, 1.1 equivalents), yielding compound 34, namely 8-bromo-4-hydroxy-3-(3-(4-nitrophenyl)benzo[ bThiophene-2-yl)-coumarin, a yellow solid, 53% yield, melting point: 164.8℃~166.4℃, its structural formula is... .

[0076] HRMS (ESI) calcd. for C 23 H 12 BrNNaO5S + (M+Na + ) 515.9512, found 515.9515. Example 30 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxy-2-hydroxycoumarin. H -Thiochroman-2-one (0.11 mmol, 1.1 equivalents) yielded compound 35, namely 4-hydroxy-3-(3-(4-nitrophenyl)benzo[ b ]Thiophen-2-yl)-2 H -Thiocarmine-2-one, pale yellow solid, yield 82%, melting point: 216.5℃~218.1℃, its structural formula is: .

[0077] HRMS (ESI) calcd. for C 23 H 13 NNaO4S2 + (M+Na + ) 454.0178, found 454.0180. Example 31 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxy-1-methylquinoline-2(1 H )-ketone (0.11 mmol, 1.1 equivalents) yielded compound 36, namely 4-hydroxy-1-methyl-3-(3-(4-nitrobenzene)benzo[ b ]Thiophene-2-yl)quinoline-2(1 H )-ketone, brown solid, 50% yield, melting point: 158.3℃~161.0℃, its structural formula is .

[0078] HRMS (ESI) calcd. for C 24 H 16 N2NaO4S + (M+Na +) 451.0723, 451.0711. Example 32 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxy-6-methyl-2-hydroxycoumarin. H -pyran-2-one (0.11 mmol, 1.1 equivalents) yielded compound 37, namely 4-hydroxy-6-methyl-3-(3-(4-nitrobenzene)benzo[ b ]Thiophen-2-yl)-2 H -Pyran-2-one, yellow solid, 82% yield, melting point 138.0℃~140.2℃, its structural formula is: .

[0079] 1 H NMR (400 MHz, DMSO- d 6) δ 8.30 (d, J = 8.8 Hz, 2H), 8.04 – 8.02 (m,1H), 7.62 – 7.59 (m, 3H), 7.46 – 7.38 (m, 2H), 6.03 (d, J = 1.2 Hz, 1H), 2.18(d, J = 0.8 Hz, 3H). 13 C NMR (151 MHz, DMSO- d 6) δ 168.81, 163.99, 163.13, 146.96,142.84, 139.97, 138.45, 134.60, 133.04, 130.56 (2C), 125.37, 125.18, 124.21(2C), 123.03, 122.55, 100.35, 94.55, 19.96. HRMS (ESI) calcd. for C 20 H 13 NNaO5S + (M+Na + ) 402.0407, found 402.0415. Examples 33-43 use other aryl fragments as nucleophiles to "anchor" them to the benzothiophene structure under anhydride activation conditions, followed by a metal-free "migration" process to prepare benzothiophene coupling products.

[0080] Example 33 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 2-hydroxynaphthyl-1,4-dione (0.11 mmol, 1.1 equivalents), yielding compound 38, namely 2-hydroxy-3-(3-(4-nitrobenzene)benzo[ b Thiophene-2-yl)naphthyl-1,4-dione, wine-red solid, yield 68%, melting point: 196.4℃~198.6℃, its structural formula is... .

[0081] HRMS (ESI) calcd. for C 24 H 13 NNaO5S + (M+Na + ) 450.0407, found 450.0397. Example 34 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with 4-hydroxyquinoline (0.11 mmol, 1.1 equivalents), yielding compound 39, namely 4-hydroxy-3-(3-(4-nitrobenzene)benzo[ b [Thiophen-2-yl]quinoline, yellow solid, yield 24%, melting point >300℃, its structural formula is: .

[0082] HRMS (ESI) calcd. for C 23 H 15 N2NaO3S + (M+H + ) 399.0798, found 399.0801. Example 35 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 4, except that 4-hydroxycoumarin is replaced with antipyrine (0.11 mmol, 1.1 equivalents), yielding compound 40, namely 1,5-dimethyl-4-(3-(4-nitrophenyl)benzo[ b ]Thiophen-2-yl)-2-phenyl-1,2-dihydro-3 H -Pyrazole-3-one, yellow solid, yield 23%, melting point: 132.5℃~133.5℃, its structural formula is: .

[0083] HRMS (ESI) calcd. for C 25H 19 N3NaO3S + (M+Na + ) 464.1039, found 464.1046. Example 36 A method for synthesizing benzothiophene coupling products using a non-metallic "anchoring-migration" strategy, the technical route of which is as follows: This includes the following steps: 2d of 3-p-nitrophenylbenzothiophene sulfoxide (0.2 mmol, 54.2 mg, 1.0 equivalent) and thiophene (0.4 mmol, 33.6 mg, 2.0 equivalent) were dissolved in 2 mL of dichloromethane. TFAA / Tf₂O (1:1, 1.5 equivalent) was added at -78 °C, and the mixture was stirred for 0.5 h. The reaction was then allowed to proceed to room temperature for 1 h. After the reaction was complete as monitored by TLC, a brown oily liquid, namely benzothiophene sulfonium salt (the first step reaction), was directly separated by preparative chromatography. The byproducts could interfere with the separation of the product, so the purification was carried out in two steps (yield 65%). Then, 160 μL of DMF was added, and the mixture was stirred at 130 °C for 12 h. After the reaction was complete as detected by TLC, the reaction solution was extracted with H₂O (20 mL) and EA (10 mL × 3), dried over anhydrous Na₂SO₄, filtered, concentrated under reduced pressure, and the crude product was purified by thin-layer chromatography to obtain compound 41, namely 3-(4-nitrophenyl)-2-(thiophene-2-yl)benzo[ b Thiophene, a yellow oily liquid, with a two-step yield of 31%.

[0084] HRMS (ESI) calcd. for C 18 H 11 NNaO2S2 + (M+Na + ) 360.0123, found 360.0131. Example 37 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 36, except that thiophene is replaced with toluene (0.15 mmol, 13.8 mg, 1.5 equivalents), followed by the addition of 80 μL of DMF and stirring at 130 °C for 24 h. The technical route is as follows: The final product was compound 42, namely 3-(4-nitrophenyl)-2-p-tolylbenzo[ b ]thiophene, o / p =1:1, yellow oily liquid, yield 51%.

[0085] 1 H NMR (600 MHz, Chloroform-d ) δ 8.26 (d, J = 8.4 Hz, 2H), 8.17 (d, J =8.4 Hz, 2H), 7.93 – 7.89 (m, 2H), 7.72 – 7.70 (m, 1H), 7.56 (dd, J = 7.2, 2.4Hz, 1H), 7.52 (d, J = 8.4 Hz, 2H), 7.44 – 7.42 (m, 5H), 7.41 – 7.36 (m, 3H), 7.34 – 7.31 (m, 2H), 7.29 – 7.26 (m, 1H), 7.20 – 7.15 (m, 4H), 7.10 (d, J = 7.8Hz, 2H), 2.34 (s, 3H), 2.03 (s, 3H). 13 C NMR (151 MHz, Chloroform- d ) δ 145.93,145.65, 141.83, 141.26, 140.94, 140.50, 138.76, 138.68, 137.95, 137.57,137.47, 136.15, 131.57, 131.23, 131.20, 130.42, 130.36 (2C), 129.56 (2C),129.41, 129.39, 129.33, 128.55 (2C), 128.42 (2C), 128.38, 127.98, 124.74,123.92, 123.88, 123.83, 122.91 (2C), 122.65 (2C), 121.49, 121.47, 121.37,121.30, 20.20, 19.11.HRMS (ESI) calcd. for C 21 H 15 NNaO2S + (M+Na + ) 368.0716, found368.0731. Example 38 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is identical to the preparation method in Example 36, except that thiophene is replaced with anisole (2.0 equivalents). This eliminates the need to separate the benzothiophene sulfonate, resulting in a one-pot yield of compound 43, namely 2-(4-methoxyphenyl)-3-(4-nitrophenyl)benzo[ b ]thiophene, o / p =1:2, yellow oily liquid, yield 50%; its structural formula is: .

[0086] NMR data of para-substituted isomers: 1 H NMR (600 MHz, Chloroform- d ) δ 8.26 (d, J =8.4 Hz, 2H), 7.90 – 7.88 (m, 1H), 7.56 –7.55 (m, 1H), 7.52 (d, J = 8.4 Hz, 2H),7.41 – 7.36 (m, 2H), 7.20 (d, J = 9.0 Hz, 2H), 6.82 (d, J = 9.0 Hz, 2H), 3.81 (s, 3H). 13 C NMR (151 MHz, Chloroform- d NMR data for ortho-substituted isomers: δ 158.70, 145.89, 141.88, 140.71, 138.78, 137.80, 131.39, 130.37 (2C), 129.91 (2C), 128.93, 123.87, 123.74, 122.93 (2C), 121.37, 121.26, 113.15 (2C), 54.26. 1 H NMR (600MHz, Chloroform- d ) δ 8.19 (d, J = 8.4 Hz, 2H), 7.91 – 7.88 (m, 1H), 7.68 – 7.66(m, 1H), 7.47 (d, J = 8.4 Hz, 2H), 7.41 – 7.36 (m, 2H), 7.34 – 7.31 (m, 1H),7.28 (dd, J = 7.2 Hz, 1.8 Hz, 1H), 6.94 (td,J = 7.8 Hz, 1.8 Hz, 1H), 6.84 – 6.81(m, 1H), 3.50 (s, 3H). 13 C NMR (151 MHz, Chloroform- d ) δ 155.57, 145.56,142.36, 137.06, 138.74, 137.78, 131.47, 129.36 (2C), 122.46 (2C), 124.61,123.70, 123.66, 121.29, 121.10, 110.24, 53.99.HRMS (ESI) calcd. forC 21 H 15 NNaO2S + (M+Na + ) 384.0665, found 384.0659. Example 39 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 38, except that thiophene is replaced with a piperonyl ring (2.0 equivalents), yielding compound 44, namely 5-(3-(4-nitrophenyl)benzo[ b ]Thiophene-2-yl)benzo[ d [1,3]dioxane, a yellow oily liquid, yield 21%; its structural formula is: .

[0087] HRMS (ESI) calcd. for C 21 H 13 NNaO4S + (M+Na + ) 398.0457, found 398.0489. Example 40 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 38, except that toluene is replaced with mesitylene (1.5 equivalents), yielding compound 45, namely 2-mesityleneyl-3-(4-nitrophenyl)benzo[ b Thiophene, a pale yellow oily liquid with a yield of 69%, has the following structural formula: .

[0088] HRMS (ESI) calcd. for C 23 H 19 NNaO2S + (M+Na+ ) 396.1029, found 396.1032. In Example 41, benzothiophene was used as a reaction substrate and benzothiophene sulfoxide was obtained after in-situ oxidation. The benzothiophene sulfoxide was then directly prepared into a benzothiophene coupling product by a one-pot method without separation and purification.

[0089] Example 41 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchor-migration" strategy is the same as the preparation method in Example 40, except that 2d is replaced with a benzothiophene sulfoxide solution obtained by in-situ oxidation of benzothiophene 1a (0.1 mmol, 13.4 mg, 1.0 equivalent), and the concentration of the benzothiophene sulfoxide solution is 0.1 mmol / L, yielding compound 46, namely 2-trimethylbenzylbenzo[ b Thiophene, a colorless oily liquid with a yield of 48%, has the following structural formula: .

[0090] 1 H NMR (400 MHz, Chloroform- d ) δ 7.90 – 7.87 (m, 1H), 7.84 – 7.81 (m,1H), 7.43 – 7.34 (m, 2H), 7.07 (t, J = 1.2 Hz, 1H), 7.00 (s, 2H), 2.38 (s, 3H), 2.22 (d, J = 1.6 Hz, 6H). Compound 46 is a known compound, and the experimental data are similar to those in the literature. Chem. Eur. J. 2024 , 30, e202303857).

[0091] Example 42 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is identical to the preparation method in Example 40, except that 4-hydroxycoumarin is replaced with 1,3-cyclopentanedione (1.1 equivalents), followed by the addition of 0.3 mL of DMF and stirring at 100 °C for 12 h to finally obtain compound 47, namely 3-hydroxy-2-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)cyclopent-2-en-1-one, a brownish-yellow oily liquid, in 51% yield, has the following structural formula: .

[0092] 1 H NMR (600 MHz, DMSO-d 6) δ 8.25 (d, J = 8.8 Hz, 2H), 7.97 – 7.42 (m,1H), 7.60 – 7.58 (m, 3H), 7.36 – 7.33 (m, 2H), 2.32 (s, 4H). 13 C NMR (151 MHz, DMSO- d 6) δ 195.41, 146.20, 144.50, 139.41, 138.52, 134.40, 130.62 (2C), 130.50, 124.82, 124.38, 123.85 (2C), 122.78, 121.69, 108.69, 70.25, 31.75,31.66. HRMS (ESI) calcd. for C 19 H 13 NNaO4S + (M+Na + ) 374.0457, found 374.0447. Example 43 A method for synthesizing benzothiophene coupling products using a non-metal-involved "anchoring-migration" strategy is the same as the preparation method in Example 42, except that 1,3-cyclopentanedione is replaced with 1,3-cyclohexanedione (1.1 equivalents), followed by the addition of 1 mL of DMF and stirring at 100 °C for 12 h to finally obtain compound 48, namely 3-hydroxy-2-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)cyclohexyl-2-en-1-one, yellow solid, yield 51%, melting point: 148.6℃~150.2℃. .

[0093] HRMS (ESI) calcd. for C 20 H 15 NNaO4S + (M+Na + ) 388.0614, found 388.0616. To determine whether the structures of compounds 47 and 48 were correct, this invention performed a one-step derivatization to obtain compound 49. The structure of this compound was determined by X-ray single-crystal derivatization, including the following steps: .

[0094] Compound 48 (0.1 mmol, 36.5 mg, 1.0 equivalent) was dissolved in ethanol (0.2 mol / L), followed by the addition of p-nitrophenylhydrazine (1.0 equivalent) and acetic acid (3.0 equivalent). The reaction was allowed to proceed at room temperature for 24 h. After TLC detection of complete reaction, K2CO3 was added to quench the reaction. The reaction solution was extracted with H2O (20 mL) and EA (10 mL × 3), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by preparative thin-layer chromatography to obtain mixture 49 (CCDC: 2489711), which was obtained by recrystallization in a mixed solvent of DCM and EA, i.e., 2-(3-(4-nitrophenyl)benzo[ b Thiophene-2-yl)-3-(2-(4-nitrophenyl)hydrazinyl)cyclohexen-1-ol, yield 27% (the compound is unstable and easily deteriorates), melting point: 246.8℃~248.4℃.

[0095] HRMS (ESI) calcd. for C 26 H 20 N4NaO5S + (M+Na + ) 523.1047, found 523.1044. Examples 44 to 51 demonstrate the use of hydroxycoumarin as a nucleophile to react with benzothiophene substituted with an aryl group at the C3 position, enabling the rapid one-pot synthesis of polycyclic aromatic hydrocarbons, which show great promise for applications in optoelectronic materials.

[0096] Example 44 A method for preparing polycyclic aromatic hydrocarbons, the technical route of which is as follows: The preparation method was the same as in Example 1, except that after obtaining the reaction solution of compound 5, it was bubbled with argon gas for 3 minutes to remove air from the system. After sealing, it was reacted at room temperature under 15W, 365nm LED light for 3 hours. After the reaction was confirmed to be complete by TLC, the reaction solution was extracted with H2O (20mL) and EA (10mL×3), dried with anhydrous Na2SO4, filtered, concentrated under reduced pressure, and the crude product was purified by preparative thin-layer chromatography to obtain compound 50, i.e., 1. H -Benzo[4',5']thiane[2',3':3,4]naphthalene[2,1- c Chromene-1-one, bright yellow solid, yield 63%.

[0097] 1 H NMR (600 MHz, Chloroform- d ) δ 9.15 (dd, J = 8.4, 3.0 Hz, 1H), 8.95 (dd,J = 8.4, 2.4 Hz, 1H), 8.83 – 8.82 (m, 1H), 8.48 (dd, J = 8.4, 2.4 Hz, 1H), 8.11 (d, J = 8.4 Hz, 1H), 7.94 – 7.91 (m, 1H), 7.74 – 7.71 (m, 1H), 7.64 (t, J =7.8 Hz, 1H), 7.60 – 7.56 (m, 3H), 7.46 – 7.43 (m, 1H). Compound 50 is a known compound, and the experimental data are similar to those in the literature. Org. Biomol. Chem. 2006, 4 , 33-35).

[0098] Example 45 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that compound 2a is replaced with 2b to obtain compound 51, namely 8-methyl-1 H -Benzo[4',5']thiane[2',3':3,4]naphthalene[2,1- c Chonen-1-one, bright yellow solid, yield 67%, melting point: 223.5℃~225.6℃, its structural formula is... .

[0099] HRMS (ESI) calcd. for C 24 H 14 NaO2S + (M+Na + ) 389.0607, found 389.0597. Example 46 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that compound 2a is replaced with 2d, and the compound is finally obtained by direct filtration in the DMF reaction solution to obtain compound 52, namely 8-nitro-1 H -Benzo[4',5']thiane[2',3':3,4]naphthalene[2,1- c Chromene-1-one, a yellowish-brown solid, yield 49%, melting point >300℃, its structural formula is: .

[0100] HRMS (ESI) calcd. for C 23 H 11 NNaO4S + (M+Na +) 420.0301, found 420.0268. Example 47 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that compound 2a is replaced with 2g, and the mixture is finally filtered directly in the DMF reaction solution to obtain compound 53, namely 1-oxo-1 H -Benzo[4',5']thiophene[2',3':3,4]naphthalene[2,1- c [Phenylen-10-cyano, bright yellow solid, yield 68%, melting point >300℃, its structural formula is] .

[0101] HRMS (ESI) calcd. for C 24 H 11 NNaO2S + (M+Na + ) 400.0403, found 400.0445. Example 48 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that compound 2a is replaced with 2g, and the mixture is ultimately filtered directly in the DMF reaction solution to obtain compound 54, namely 9-methylbenzo[4,5]thiazole[2,3- g Tryptophan [4,3- e ]Pyrazole-1(9 H )-ketone, white solid, yield 58%, melting point >300℃, its structural formula is .

[0102] HRMS (ESI) calcd. for C 21 H 12 N2NaO2S + (M+Na + ) 379.0512, found 379.0537. Example 49 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that 4-hydroxycoumarin is replaced with 4-hydroxy-2-hydroxycoumarin. H -Thiochroman-2-one, yielding compound 55, i.e., 1 H -Benzo[4',5']thiazole[2',3':3,4]naphthalene[2,1- c Thiazol-1-one, a bright yellow solid, 73% yield, melting point: 145.5℃~148.7℃, with the following structural formula: .

[0103] HRMS (ESI) calcd. for C 23 H 12 NaOS2 + (M+Na + ) 391.0222, found 391.0178. Example 50 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that 4-hydroxycoumarin is replaced with 4-hydroxy-1-methylquinoline-2(1 H )-ketone, yielding compound 56, namely 2-methylbenzo[ k ]Benzo[4,5]thiazole[2,3- i ]Phenyranidine-1(2 H )-ketone, pale yellow solid, yield 42%, melting point: 248.7℃~251.2℃. Its structural formula is: .

[0104] HRMS (ESI) calcd. for C 24 H 15 NNaOS + (M+Na + ) 388.0767, found 388.0771. Example 51 A method for preparing a polycyclic aromatic hydrocarbon compound is the same as that in Example 44, except that 4-hydroxycoumarin is replaced with 4-hydroxy-6-methyl-2-hydroxycoumarin. H -pyran-2-one, yielding compound 57, namely 3-methyl-1 H -benzo[ f ]Benzo[4,5]thiazo[3,2- h Isobenzopyran-1-one, a brownish-yellow solid, yield 62%, melting point: 201.4℃~204.3℃, its structural formula is: .

[0105] HRMS (ESI) calcd. for C 20 H 12 NaO2S + (M+Na + ) 339.0450, found 339.0483. Compounds 51 to 57 of this invention share the same parent skeleton as compound 50 (benzothiophene-coumarin fused ring system), with substituents (such as methyl, nitro, cyano, methoxy, etc.) introduced only on the benzothiophene or coumarin fragment. This series of compounds retains the conjugated planar structure and rigid skeleton characteristics of compound 50, therefore their photophysical properties (including UV-Vis absorption characteristics, fluorescence emission mechanism, and quantum yield trend) are basically similar to those of compound 50.

[0106] The X-ray single crystal structure and data are shown in Tables 1 and 2: Table 1 shows the X-ray single crystal structure and data of compound 18. Table 2 shows the X-ray single crystal structure and data of compound 49. It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for synthesizing benzothiophene coupling products using a non-metallic "anchoring-migration" strategy, characterized in that, Includes the following steps: Using benzothiophene compounds or benzothiophene sulfoxide compounds as reaction substrates, the reaction substrates are mixed with aryl nucleophiles in the presence of an anhydride activator and solvent, and a nucleophilic substitution reaction is carried out to obtain benzothiophene sulfonate. The aryl nucleophile is selected from 4-hydroxycoumarin, 5-chloro-4-hydroxycoumarin, 4-hydroxy-6-methylcoumarin, 4-hydroxy-6-methoxycoumarin, 6-chloro-4-hydroxycoumarin, 6-bromo-4-hydroxycoumarin, 4-hydroxy-7-methylcoumarin, 4-hydroxy-7-methoxycoumarin, 7-bromo-4-hydroxycoumarin, 4-hydroxy-8-methylcoumarin, 8-bromo-4-hydroxycoumarin, 4-hydroxy-2-hydroxycoumarin. H -Thiochroman-2-one, 4-hydroxy-1-methylquinoline-2(1 H )-ketone, 4-hydroxy-6-methyl-2 H -Pyran-2-one, 4-hydroxyquinoline, antipyrine, 2-hydroxynaphthyl-1,4-dione, 1,3-cyclopentanedione, 1,3-cyclohexanedione, thiophene, toluene, anisole, piperonyl or mesitylene; When benzothiophene sulfonate is mixed with an organic solvent, a metal-free intramolecular migration reaction is carried out. After the carbon-hydrogen bond at the C2 position of the benzothiophene sulfonate is polarized, the α-carbon segment of the aryl nucleophile migrates from the sulfur atom to the C2 position, and simultaneously CS + The bond breaks, and a new C-C bond is eventually formed at the C2 position of the benzothiophene sulfonate to obtain the benzothiophene coupling product; The conditions for the intramolecular migration reaction are: stirring at 90℃~150℃ for 3h~24h.

2. The method according to claim 1, characterized in that, Based on 1.0 equivalent of the reaction substrate, the amount of aryl nucleophile is 1.1 to 2.0 equivalents, and the amount of acid anhydride activator is 1.5 to 3.0 equivalents.

3. The method according to claim 1, characterized in that, Benzothiophene compounds are selected from .

4. The method according to claim 1, characterized in that, Benzothiophene sulfoxide compounds are selected from .

5. The method according to claim 1, characterized in that, The conditions for the nucleophilic substitution reaction are: stirring at -40℃ or -78℃ for 0.5h to 1h.

6. A benzothiophene coupling product obtained by the method according to any one of claims 1 to 5, characterized in that, The benzothiophene coupling product is , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , or .

7. A polycyclic aromatic hydrocarbon compound, characterized in that, The polycyclic aromatic hydrocarbon compound is prepared by photocyclization reaction of the benzothiophene coupling product of claim 6; Among them, the benzothiophene coupling product is selected from , , , , , , , , , , , , , , , , , , , , , , , , , , , , , or .

8. The polycyclic aromatic hydrocarbon compound according to claim 7, characterized in that, The conditions for the photocyclization reaction are: 2h to 6h under light irradiation at room temperature, wavelength of 365nm to 455nm, and intensity of 15W.

9. The polycyclic aromatic hydrocarbon compound according to claim 7, characterized in that, The polycyclic aromatic hydrocarbons are , , , , , , , or .

Images