Method for driving air to oxidize benzyl carbon-hydrogen bonds by visible light

Abstract

The invention relates to a method for driving air to oxidize a benzyl carbon-hydrogen bond by visible light, which comprises the following steps: adding an alkyl substituted benzene compound and 1, 1 '-binaphthyl-2, 2'-bisdiphenylphosphine into a solvent, and carrying out driving reaction in the atmosphere at room temperature by visible light for 48 hours to obtain a reaction solution; quenching the reaction liquid by using a saturated ammonium chloride solution, extracting by using ethyl acetate to obtain an organic phase, drying the organic phase by using anhydrous sodium sulfate, and performing rotary evaporation to obtain a concentrate; and carrying out silica gel column chromatography on the concentrate to obtain the Csp3-H bond oxidation product. According to the method, no extra oxidizing agent needs to be added, only oxygen in the atmosphere is used for oxidation, no toxic and polluting catalysts are added into the whole system, by-products are green and environmentally friendly, and pollution to the environment is small.

Description

Technical Field

[0001] The invention relates to a method for synthesizing aldehydes, ketones and amides, and in particular to a method for visible light driven air oxidation of benzyl carbon-hydrogen bonds. Background Art

[0002] Aldehydes, ketones, and amides are an important class of compounds that are widely used in the preparation of fragrances, drugs, agrochemicals, and polymers. Therefore, the green synthesis of these compounds has attracted the attention of chemists. Direct oxidation of C—H bonds of alkyl-substituted benzene compounds is a promising synthetic method because the raw materials are easily available. Traditionally, this transformation is accomplished using metal reagents (such as chromium, manganese, cerium, cobalt, etc.) or organic oxidants (such as PCC, IBX). However, these methods are generally accomplished by using stoichiometric oxidants, such as potassium permanganate, peroxide, and periodide (IBX). Because common chemical oxidants are mostly flammable, explosive, and hazardous chemicals, the use of these reagents also brings a series of problems that limit their industrial application. For example: there are many reaction by-products and poor atom economy; the storage and experimental operation of chemical reagents are relatively cumbersome; the use of metal oxidants may also lead to metal residue problems in the product.

[0003] To address these issues, the development of new, relatively green methods for benzylic oxidation has been well developed. Photoredox-catalyzed benzylic carbon-hydrogen bond oxidation of aromatic hydrocarbons has also recently gained momentum. A series of reactions using different photocatalysts can effectively convert these raw materials into oxidation products such as aldehydes, ketones, and carboxylic acids. In 2000, Fukuzumi and colleagues achieved groundbreaking results in this area, first using acridine salt catalysts (such as 10-methyl-9-phenyl perchlorate, Ph-Acr + ClO4 － ) as a photocatalyst, 2010, The research group first used flavin and its derivatives (Flavin) as photocatalysts. However, both studies required the use of pure oxygen as an oxidant, which not only poses a risk of fire and explosion, but also increases energy and cost requirements. In recent years, some new catalytic systems have also been discovered and reported. In 2018, Jiang Zhiyong's group reported the application of tetrahalide iron salts in this photooxidation process; in 2020, Fu Hua's group used sodium trifluoromethanesulfonate to achieve the photooxidative synthesis of a series of ketone compounds; in 2021, Szpilman's group used 9,10-dibromoanthracene as a photocatalyst for this reaction. Although these studies were able to directly use air as an oxidant, the yields were low for many substrates, which may be due to the conversion of aldehydes to the corresponding acids. In fact, over-oxidation is a common problem in this field because aldehydes can be further converted into carboxylic acids by air under sunlight conditions without any catalysts or additives. In addition, site selectivity becomes challenging when multiple methyl groups are present.

[0004] Although photocatalysts can activate molecular oxygen to promote the conversion of organic compounds, they also produce byproducts such as water or hydrogen peroxide. However, existing methods have some disadvantages, such as the use of transition metal catalysts, stoichiometric oxidants or additives, which will lead to the production of stoichiometric hazards, toxic byproducts and waste.

[0005] Therefore, there is an urgent need to develop a simple, convenient, and more sustainable photooxidation technology that can effectively synthesize aromatic aldehydes using air while preventing over-oxidation and exhibiting high selectivity. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for oxidizing benzyl carbon-hydrogen bonds by air driven by visible light under mild conditions and with little environmental pollution.

[0007] In order to solve the above problems, the present invention discloses a method for visible light driven air oxidation of benzyl carbon-hydrogen bonds, characterized in that: the method refers to adding an alkyl substituted benzene compound and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to a solvent, and driving the reaction with visible light in the atmosphere at room temperature, and obtaining a reaction solution after 48 hours; the reaction solution is quenched with a saturated ammonium chloride solution and extracted with ethyl acetate to obtain an organic phase, the organic phase is first dried with anhydrous sodium sulfate, and then rotary evaporated to obtain a concentrate; the concentrate is subjected to silica gel column chromatography to obtain C sp3 -H bond oxidation product; the C sp3 The structural formula of the -H bond oxidation product is shown below:

[0008]

[0009] Where: R 1is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a vinyl group, an ethynyl group, a phenyl group, and an N,N-dimethyl group.

[0010] When R 2 When it is a hydrogen atom, R 1 is any one of methyl, methoxy, tert-butyl, N,N-dimethyl, chlorine, and bromine; when R 2 When it is methyl, R 1 is a methoxy group or a bromine atom; when R 2 When it is vinyl, R 1 is a methoxy group or a hydrogen atom; when R 2 When it is ethynyl, R 1 is a hydrogen atom; when R 2 When it is phenyl, R 1 is a hydrogen atom; when R 2 When it is N,N-dimethyl, R 1 A hydrogen atom.

[0011] The molar ratio of the 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to the alkyl-substituted benzene compound is 1:20.

[0012] The ratio of the alkyl-substituted benzene compound to the solvent is 0.3 mmol:1.0 mL.

[0013] The alkyl substituted benzene compound refers to any one of the following structures:

[0014]

[0015] Where: R 1 is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a phenyl group, a vinyl group, an ethynyl group, and an N,N-dimethyl group.

[0016] The solvent is acetonitrile at a concentration of 0.3 M.

[0017] The visible light refers to LED white light.

[0018] The extraction was performed 3 times.

[0019] The rotary evaporation conditions are a temperature of 40° C. and a pressure of 1.3 kPa.

[0020] The silica gel column chromatography conditions refer to using 200-300 mesh silica gel, and the eluent is a mixture of petroleum ether and ethyl acetate mixed evenly in a volume ratio of 50mL:1mL.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention does not require the addition of additional oxidants, and only uses oxygen in the atmosphere for oxidation. The entire system does not add any toxic or polluting catalysts. At the same time, LED white light is used as a visible light source, and the by-products are green and environmentally friendly, with little pollution to the environment.

[0023] 2. The present invention synthesizes aldehydes, ketones and amide compounds in one step by a photochemical method. The entire synthesis reaction conditions are mild, the operation is simple, and the substrate has wide practicality.

[0024] 3. The present invention does not have the phenomenon of over-oxidation, and when multiple methyl groups are present, the site selectivity is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0026] Figure 1 For the present invention 2b 1 H NMR spectrum.

[0027] Figure 2 For the present invention 2b 13 C NMR spectrum.

[0028] Figure 3 For the present invention 2g 1 H NMR spectrum.

[0029] Figure 4 For the present invention 2g 13 C NMR spectrum.

[0030] Figure 5 For the present invention 2i 1 H NMR spectrum.

[0031] Figure 6 For the present invention 2i 13 C NMR spectrum. DETAILED DESCRIPTION

[0032] A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds, the method comprising adding an alkyl substituted benzene compound and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to a solvent, and driving the reaction in the atmosphere at room temperature using an LED white light lamp as visible light, and obtaining a reaction solution after 48 hours. The molar ratio of 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to the alkyl substituted benzene compound is 1:20; the ratio of the alkyl substituted benzene compound to the solvent is 0.3 mmol:1.0 mL; the solvent is acetonitrile with a concentration of 0.3 M; the alkyl substituted benzene compound is any one of the following structures:

[0033]

[0034] Where: R 1 is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a phenyl group, a vinyl group, an ethynyl group, and an N,N-dimethyl group.

[0035] The reaction solution was quenched with saturated ammonium chloride solution and extracted with ethyl acetate three times. The organic phases were combined and dried with anhydrous sodium sulfate, and then rotary evaporated to constant weight at 40°C and 1.3 kPa to obtain a concentrate. The concentrate was chromatographed on a silica gel column using 200-300 mesh silica gel. The eluent was a mixture of petroleum ether and ethyl acetate in a volume ratio of 50 mL:1 mL. After the chromatography, C was obtained. sp3 -H bond oxidation product. sp3 The structural formula of the -H bond oxidation product is shown below:

[0036]

[0037] Where: R 1 is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a vinyl group, an ethynyl group, a phenyl group, and an N,N-dimethyl group.

[0038] Preferred: When R 2 When it is a hydrogen atom, R 1 is any one of methyl, methoxy, tert-butyl, N,N-dimethyl, chlorine, and bromine; when R 2 When it is methyl, R 1 is a methoxy group or a bromine atom; when R 2 When it is vinyl, R 1 is a methoxy group or a hydrogen atom; when R 2 When it is ethynyl, R 1 is a hydrogen atom; when R2 When it is phenyl, R 1 is a hydrogen atom; when R 2 When it is N,N-dimethyl, R 1 A hydrogen atom.

[0039] The general reaction formula is as follows:

[0040]

[0041] Example 1 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds, the method is to add alkyl substituted benzene compounds and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to a solvent, and use LED white light as visible light to drive the reaction in the atmosphere at room temperature, and obtain a reaction solution after 48 hours. The molar ratio of 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP) to the alkyl substituted benzene compound is 1:20; the ratio of the alkyl substituted benzene compound to the solvent is 0.3mmol:1.0mL; the solvent is acetonitrile with a concentration of 0.3M; the reaction solution is quenched with a saturated ammonium chloride solution and extracted with ethyl acetate three times, and the organic phase is combined, the organic phase is first dried with anhydrous sodium sulfate, and then rotary evaporated to constant weight at a temperature of 40°C and a pressure of 1.3kPa to obtain a concentrate; the concentrate is subjected to silica gel column chromatography using 200-300 mesh silica gel, and the eluent is a mixture of petroleum ether and ethyl acetate mixed in a volume ratio of 50mL:1mL. After column chromatography, p-methoxybenzaldehyde (2a) is obtained.

[0042] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methyl; R 2 A hydrogen atom.

[0043] The obtained product is an oily liquid (21.6 mg, 60%), and its structural formula is shown below:

[0044] 1 H NMR (400MHz, CDCl3) δ9.94 (s, 1H), 7.75 (d, J = 8.0Hz, 2H), 7.30 (dJ = 8.0Hz, 2H), 2.42 (s, 3H).

[0045] 13 C NMR (100MHz, CDCl3) δ191.8,145.4,129.7,129.6,21.7.

[0046] HRMS(ESI,m / z):Calculated for[C8H8O](M+Na) +143.0467, found 143.0468.

[0047] Example 2 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2b).

[0048] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methoxy; R 2 A hydrogen atom.

[0049] The obtained product is an oily liquid (26.5 mg, 65%), and its structural formula is shown below:

[0050] 1 H NMR (400MHz, CDCl3) δ9.88 (s, 1H), 7.84 (d, J = 8.8Hz, 2H), 7.00 (d, J = 8.7Hz, 2H), 3.89 (s, 3H). Such as Figure 1 shown.

[0051] 13 C NMR (100MHz, CDCl3) δ190.8, 164.6, 131.9, 129.9, 114.3, 55.5. Figure 2 shown.

[0052] HRMS(ESI,m / z):Calculated for[C8H8O2](M+Na) + 159.0417, found 159.0419.

[0053] Example 3 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-tert-butylbenzaldehyde (2c).

[0054] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is tert-butyl; R 2 A hydrogen atom.

[0055] The obtained product is an oily liquid (29.7 mg, 61%), and its structural formula is shown below:

[0056] 1 H NMR (400MHz, CDCl3) δ9.78 (s, 1H), 7.82 (d, J = 8.2Hz, 2H), 7.55 (d, J = 8.2Hz, 2H), 1.35 (s, 9H).

[0057] 13 C NMR (100MHz, CDCl3) δ192.0, 158.4, 134.0, 129.6, 125.9, 35.3.

[0058] HRMS(ESI,m / z):Calculated for[C 11 H 14 O](M+Na) + 185.0937, found 185.0938.

[0059] Example 4 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2d).

[0060] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is N,N-dimethyl; R 2 A hydrogen atom.

[0061] The obtained product is an oily liquid (31.8 mg, 71%), and its structural formula is shown below:

[0062] 1 H NMR (400MHz, CDCl3) δ9.73 (s, 1H), 7.72 (d, J = 8.8Hz, 2H), 6.69 (d, J = 8.8Hz, 2H), 3.07 (s, 6H).

[0063] 13 C NMR (100MHz, CDCl3) δ190.2,154.2,131.8,125.1,110.9,40.0.

[0064] HRMS(ESI,m / z):Calculated for[C9H 11 NO](M+Na) + 172.0733, found 172.0736.

[0065] Example 5 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2e).

[0066] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a chlorine atom; R 2 A hydrogen atom.

[0067] The obtained product is an oily liquid (25.2 mg, 60%), and its structural formula is shown below:

[0068] 1 H NMR (400MHz, CDCl3) δ9.99 (s, 1H), 7.82 (d, J = 8.6Hz, 2H), 7.51 (d, J = 8.8Hz, 2H).

[0069] 13 C NMR (100MHz, CDCl3) δ190.8,140.9,134.7,130.9,129.4.

[0070] HRMS(ESI,m / z):Calculated for[C7H5ClO](M+Na) + 162.9921, found 162.9923.

[0071] Example 6 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2f).

[0072] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a bromine atom; R 2 A hydrogen atom.

[0073] The obtained product is an oily liquid (34.7 mg, 63%), and its structural formula is shown below:

[0074] 1 H NMR (400MHz, CDCl3) δ9.73 (s, 1H), 7.75 (d, J = 8.6Hz, 2H), 6.72 (d, J = 8.6Hz, 2H).

[0075] 13 C NMR (100MHz, CDCl3) δ191.0,135.1,132.4,130.9,129.7.

[0076] HRMS(ESI,m / z):Calculated for[C7H5BrO](M+Na) + 206.9416, found 206.9415.

[0077] Example 7 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2 g).

[0078] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methyl; R 2A hydrogen atom.

[0079] The obtained product is an oily liquid (7.9 mg, 63%), and its structural formula is shown below:

[0080] 1 H NMR (400MHz,CDCl3)δ9.97(s,1H),7.68-7.66(m,2H),7.42-7.40(m,2H),2.41(s,3H). Figure 3 shown.

[0081] 13 C NMR (100 MHz, CDCl3) δ 192.5, 138.8, 136.4, 135.2, 129.9, 128.8, 127.1, 21.0. Figure 4 shown.

[0082] HRMS(ESI,m / z):Calculated for[C8H8O](M+Na) + 144.0501, found 144.0500.

[0083] Example 8 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2h).

[0084] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a bromine atom; R 2 A hydrogen atom.

[0085] The obtained product is an oily liquid (7.7 mg, 14%), and its structural formula is shown below:

[0086] 1 H NMR (400MHz, CDCl3) δ9.97 (s, 1H), 8.02 (s, 1H), 7.81 (d, J = 8.0Hz, 1H), 7.76 (d, J = 8.0Hz, 1H).

[0087] 13 C NMR (100MHz, CDCl3) δ190.7,138.1,137.3,132.4,130.6,128.4,123.4.

[0088] HRMS(ESI,m / z):Calculated for[C7H5BrO](M+Na) + 206.9416, found 206.9416.

[0089] Example 9 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2i).

[0090] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methoxy; R 2 A hydrogen atom.

[0091] The obtained product is an oily liquid (12.7 mg, 31%), and its structural formula is shown below:

[0092] 1 H NMR (400MHz,CDCl3)δ10.47(s,1H),7.84-7.81(m,1H),7.57-7.50(m,1H),7.04-6.98(m,2H),3.92(s,3H). Figure 5 shown.

[0093] 13 C NMR (100 MHz, CDCl3) δ 189.7, 161.8, 135.9, 128.5, 124.8, 120.6, 111.6, 55.6. Figure 6 shown.

[0094] HRMS(ESI,m / z):Calculated for[C8H8O2](M+Na) + 144.0501, found 144.0503.

[0095] Example 10 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (2j).

[0096] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a bromine atom; R 2 A hydrogen atom.

[0097] The obtained product is an oily liquid (8.2 mg, 15%), and its structural formula is shown below:

[0098] 1 H NMR (400MHz, CDCl3) δ10.41(s,1H),7.93-7.91(m,1H),7.67-7.64(m,1H),7.48-7.41(m,2H).

[0099] 13C NMR (100MHz, CDCl3) δ191.8, 135.3, 133.5, 129.8, 127.9, 127.1.

[0100] HRMS(ESI,m / z):Calculated for[C7H5BrO](M+Na) + 206.9416, found 206.9420.

[0101] Example 11 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3a).

[0102] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methoxy; R 2 It is methyl.

[0103] The obtained product is an oily liquid (36.0 mg, 80%), and its structural formula is shown below:

[0104] 1 H NMR (400MHz, CDCl3) δ7.95 (d, J = 8.0 Hz, 2H), 6.95 (d, J = 8.0 Hz, 2H), 3.88 (s, 3H), 2.57 (s, 3H).

[0105] 13 C NMR (100MHz, CDCl3) δ196.6, 163.5, 130.9, 130.3, 114.2, 55.8, 26.7.

[0106] HRMS(ESI,m / z):Calculated for[C9H 10 O2](M+Na) + 173.0573, found 173.0576.

[0107] Example 12 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3b).

[0108] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a bromine atom; R 2 It is methyl.

[0109] The obtained product is an oily liquid (44.5 mg, 75%), and its structural formula is shown below:

[0110] 1 H NMR (400MHz, CDCl3) δ7.84 (d, J = 8.0 Hz, 2H), 7.62 (d, J = 8.0 Hz, 2H), 2.61 (s, 3H).

[0111] 13 C NMR (100MHz, CDCl3) δ197.1, 135.9, 131.9, 129.9, 128.3, 26.6.

[0112] HRMS(ESI,m / z):Calculated for[C8H7BrO](M+Na) + 220.9572, found 220.9574.

[0113] Example 13 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3c).

[0114] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a hydrogen atom; R 2 It is phenyl.

[0115] The obtained product is an oily liquid (24.5 mg, 45%), and its structural formula is shown below:

[0116] 1 H NMR (400MHz, CDCl3) δ7.84–7.78(m,4H),7.59(t,J=7.4Hz,2H), 7.49(t,J=7.6Hz,4H).

[0117] 13 C NMR (100MHz, CDCl3) δ196.7, 137.6, 132.4, 129.9, 128.2.

[0118] HRMS(ESI,m / z):Calculated for[C 13 H 10 O](M+Na) + 205.0624, found 205.0627.

[0119] Example 14 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3d).

[0120] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 2 It is methyl.

[0121] The obtained product is an oily liquid (32.1 mg, 63%), and its structural formula is shown below:

[0122] 1 H NMR (400MHz, CDCl3) δ8.46 (s, 1H), 8.04 (dd, J = 8.6, 1.7Hz, 1H), 7.96 (d, J = 8.0Hz, 1H), 7.91–7.86 (m, 2H), 7.62–7.53 (m, 2H), 2.73 (s, 3H).

[0123] 13 C NMR (100MHz, CDCl3) δ196.7, 137.6, 132.4, 129.9, 128.2.

[0124] HRMS(ESI,m / z):Calculated for[C 12 H 10 O](M+Na) + 193.0624, found 193.0626.

[0125] Example 15 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3e).

[0126] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a hydrogen atom; R 2 For vinyl.

[0127] The obtained product is an oily liquid (25.7 mg, 65%), and its structural formula is shown below:

[0128] 1 H NMR (400MHz, CDCl3) δ7.94(d,J=7.8Hz,2H),7.58(t,J=7.6Hz,1H),7.48(t,J=7.8Hz ,2H), 7.15(dd,J=17.2,10.6Hz,1H), 6.45(d,J=17.2Hz,1H), 5.94(d,J=10.6Hz,1H).

[0129] 13 C NMR (100MHz, CDCl3) δ191.0, 137.1, 133.0, 132.3, 130.1, 128.6, 128.5.

[0130] HRMS(ESI,m / z):Calculated for[C9H8O](M+Na) + 156.0501, found 156.0505.

[0131] Example 16 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3f).

[0132] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is methoxy; R 2 For vinyl.

[0133] The obtained product is an oily liquid (36.4 mg, 75%), and its structural formula is shown below:

[0134] 1 H NMR (400MHz, CDCl3) δ7.96 (d, J = 8.6 Hz, 2H), 7.17 (dd, J = 17.0, 10.6 Hz, 1H), 6. 96(d,J=8.6Hz,2H), 6.41(d,J=17.0,1H), 5.86(d,J=10.6Hz,1H), 3.87(s,3H).

[0135] 13 C NMR (100MHz, CDCl3) δ189.3, 163.6, 132.2, 131.1, 130.3, 129.4, 113.9, 55.5.

[0136] HRMS(ESI,m / z):Calculated for[C 10 H 10 O2](M+Na) + 185.0573, found 185.0577.

[0137] Example 17 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3 g).

[0138] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 2 For vinyl.

[0139] The obtained product is an oily liquid (38.2 mg, 70%), and its structural formula is shown below:

[0140] 1H NMR (400MHz, CDCl3) δ8.45(s,1H),8.02(d,J=8.6Hz,1H), 7.95(d,J=8.0Hz,1H), 7.90(d,J=8.6,1H), 7.87(d,J=8.2Hz,1H), 7.59(t,J=7.4Hz,1H), 7.54(t,J=7.4Hz,1H), 7.31(dd,J=17.2,10.6Hz,1H), 6.49(d,J=17.2Hz,1H), 5.96(d,J=10.6Hz,1H).

[0141] 13 C NMR (100MHz, CDCl3) δ190.9,135.6,134.7,132.6,132.5,130.4,130.2,129.6,128.7,128.5,127.9,126.9,124.5.

[0142] HRMS(ESI,m / z):Calculated for[C 13 H 10 O](M+Na) + 205.0624, found 205.0626.

[0143] Example 18 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3h).

[0144] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a hydrogen atom; R 2 It is ethynyl.

[0145] The obtained product is an oily liquid (36.4 mg, 75%), and its structural formula is shown below:

[0146] 1 H NMR (400MHz, CDCl3) δ8.16 (dd, J=8.4, 1.2Hz, 2H), 7.65-7.58 (m, 1H), 7.49 (t, J=7.7Hz, 2H), 3.46 (s, 1H).

[0147] 13 C NMR (100MHz, CDCl3) δ177.5, 136.2, 134.6, 129.8, 128.8, 81.0, 80.3.

[0148] HRMS(ESI,m / z):Calculated for[C9H6O](M+Na) + 154.0344, found 154.0345.

[0149] Example 19 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3i).

[0150] Among them: The structural formula of alkyl substituted benzene compounds is

[0151] The obtained product is an oily liquid (26.2 mg, 70%), and its structural formula is shown below:

[0152] 1 H NMR (400MHz, CDCl3) δ8.03-8.00(m,1H), 7.47-7.43(m,1H), 7.30-7.23(m,2H), 2.97-2.93(m,2H), 2.66-2.62(m,2H), 2.15-2.10(m,2H).

[0153] 13 C NMR (100MHz, CDCl3) δ198.4, 146.4, 133.4, 132.7, 128.7, 127.2, 126.6, 39.1, 29.6, 23.2.

[0154] HRMS(ESI,m / z):Calculated for[C 10 H 10 O](M+Na) + 170.0657, found 170.0660.

[0155] Example 20 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3j).

[0156] Among them: The structural formula of alkyl substituted benzene compounds is

[0157] The obtained product is an oily liquid (39.2 mg, 73%), and its structural formula is shown below:

[0158] 1 H NMR (400MHz, CDCl3) δ7.69-7.66(m,2H), 7.55-7.48(m,4H), 7.33-7.28(m,2H).

[0159] 13 C NMR (100MHz, CDCl3) δ194.0, 144.4, 134.7, 134.2, 129.1, 124.3, 124.2, 120.3.

[0160] HRMS(ESI,m / z):Calculated for[C 13 H8O](M+Na) + 203.0467, found 203.0470.

[0161] Example 21 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3k).

[0162] Among them: The structural formula of alkyl substituted benzene compounds is

[0163] The obtained product was a yellow solid (42.8 mg, 73%), and its structural formula is shown below:

[0164] 1 H NMR (400MHz, CDCl3) δ8.33(dd,J=8.0,2.0Hz,2H),,7.72-7.68(m,2H),7.47(d,J=8.4,2H),7.37(t,J=7.6Hz,2H).

[0165] 13 C NMR (100MHz, CDCl3) δ177.2, 156.2, 134.8, 126.8, 123.9, 121.9, 118.0.

[0166] HRMS(ESI,m / z):Calculated for[C 13 H8O2](M+Na) + 219.0417, found 219.0420.

[0167] Example 22 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3l).

[0168] Among them: The structural formula of alkyl substituted benzene compounds is

[0169] The obtained product was a yellow solid (56.8 mg, 70%), and its structural formula is shown below:

[0170] 1H NMR (400MHz, CDCl3) δ8.60 (dd, J=8.0, 1.5Hz, 2H), 7.74-7.70 (m, 2H), 7.68-7.64 (m ,1H),7.53-7.48(m,2H),7.39-7.36(m,2H),7.29-7.26(m,2H),6.76(d,J=9.0,2H).

[0171] 13 C NMR (100MHz, CDCl3) δ178.3, 143.3, 139.2, 133.4, 131.1, 130.3, 129.8, 127.5, 122.1, 121.8, 117.0.

[0172] HRMS(ESI,m / z):Calculated for[C 19 H 13 NO](M+Na) + 294.0889, found 294.0894.

[0173] Example 23 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (3m).

[0174] Among them: The structural formula of alkyl substituted benzene compounds is

[0175] The obtained product was a solid (40.8 mg, 75%), and its structural formula is shown below:

[0176] 1 H NMR (400MHz, CDCl3) δ8.08(d,J=8.2Hz,1H),7.96(d,J=7.0Hz,1H),7.82(d,J=8.4 Hz,1H),7.74-7.70(m,1H),7.62-7.58(m,1H),7.47(d,J=6.8Hz,1H),3.82(s,2H).

[0177] 13 C NMR (100MHz, CDCl3) δ203.1, 143.2, 135.2, 135.0, 131.6, 131.1, 128.5, 128.2, 124.1, 121.6, 121.5, 42.2.

[0178] HRMS(ESI,m / z):Calculated for[C 12 H8O](M+Na) +192.0501, found 192.0505.

[0179] Example 24 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (4a).

[0180] Among them: The structural formula of alkyl substituted benzene compounds is Where: R 1 is a hydrogen atom; R 2 It is N,N-dimethyl.

[0181] The obtained product is an oily liquid (33.4 mg, 75%), and its structural formula is shown below:

[0182] 1 H NMR (400MHz, CDCl3) δ7.42-7.36(m,5H), 3.08(s,3H), 2.96(s,3H).

[0183] 13 C NMR (100MHz, CDCl3) δ171.8,136.5,129.6,128.5,127.2,39.7,35.5.

[0184] HRMS(ESI,m / z):Calculated for[C9H 11 NO](M+Na) + 173.0766, found 173.0770.

[0185] Example 25 A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds is the same as Example 1 to obtain p-methoxybenzaldehyde (4b).

[0186] Among them: The structural formula of alkyl substituted benzene compounds is

[0187] The obtained product is an oily liquid (21.7 mg, 45%), and its structural formula is shown below:

[0188] 1 H NMR (400MHz, CDCl3) δ8.07 (d, J = 7.6 Hz, 1H), 7.41-7.33 (m, 2H), 7.17 (d, J = 7.2 Hz, 1H), 3.57 (t, J = 6.7 Hz, 2H), 3.16 (s, 3H), 3.01 (t, J = 6.7 Hz, 2H).

[0189] 13C NMR(100MHz,CDCl3)δ164.7,137.9,131.4,129.3,128.0,126.9,126.8,48.1,35.1,27.9.

[0190] HRMS(ESI,m / z):Calculated for[C 10 H 11 NO](M+Na) + 184.0733,found184.0735.。

Claims

1. A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds, characterized in that: The method comprises adding an alkyl substituted benzene compound and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine to a solvent, and driving the reaction with visible light in the atmosphere at room temperature, and obtaining a reaction solution after 48 hours; the reaction solution is quenched with a saturated ammonium chloride solution, extracted with ethyl acetate, and an organic phase is obtained; the organic phase is first dried with anhydrous sodium sulfate, and then rotary evaporated to obtain a concentrate; the concentrate is subjected to silica gel column chromatography to obtain C sp3 -H bond oxidation product; the C sp3 The structural formula of the -H bond oxidation product is shown below: Where: R 1 is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a vinyl group, an ethynyl group, a phenyl group, and an N,N-dimethyl group.

2. A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds as claimed in claim 1, characterized in that: When R 2 When it is a hydrogen atom, R 1 is any one of methyl, methoxy, tert-butyl, N,N-dimethyl, chlorine, and bromine; when R 2 When it is methyl, R 1 is a methoxy group or a bromine atom; when R 2 When it is vinyl, R 1 is a methoxy group or a hydrogen atom; when R 2 When it is ethynyl, R 1 is a hydrogen atom; when R 2 When it is phenyl, R 1 is a hydrogen atom; when R 2 When it is N,N-dimethyl, R 1 A hydrogen atom.

3. The method of claim 1, wherein: The molar ratio of the 1,1'-binaphthyl-2,2'-bisdiphenylphosphine to the alkyl-substituted benzene compound is 1:

20.

4. The method of claim 1, wherein: The ratio of the alkyl-substituted benzene compound to the solvent is 0.3 mmol:1.0 mL.

5. A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds according to any one of claims 1, 3 to 4, characterized in that: The alkyl substituted benzene compound refers to any one of the following structures: Where: R 1 is any one of a methyl group, a methoxy group, a tert-butyl group, an N,N-dimethyl group, a chlorine atom, a bromine atom, and a hydrogen atom; R 2 It is any one of a hydrogen atom, a methyl group, a phenyl group, a vinyl group, an ethynyl group, and an N,N-dimethyl group.

6. A method for visible light driven air oxidation of benzyl carbon-hydrogen bonds as claimed in claim 1 or 4, characterized in that: The solvent was acetonitrile at a concentration of 0.3 M.

7. The method of claim 1 for visible light driven air oxidation of benzyl carbon-hydrogen bonds, characterized in that: The visible light refers to LED white light.

8. The method of claim 1 for visible light driven air oxidation of benzyl carbon-hydrogen bonds, characterized in that: The extraction was performed 3 times.

9. The method of claim 1 for visible light driven air oxidation of benzyl carbon-hydrogen bonds, characterized in that: The rotary evaporation conditions are a temperature of 40° C. and a pressure of 1.3 kPa.

10. The method of claim 1, wherein: The silica gel column chromatography conditions refer to using 200-300 mesh silica gel, and the eluent is a mixture of petroleum ether and ethyl acetate mixed evenly in a volume ratio of 50mL:1mL.

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