Synthetic method for alkene boron arylation through photocatalysis

Abstract

The invention relates to the technical field of synthesis of organic boron compounds, and discloses a synthesis method for photo-catalytic alkene boron arylation, and according to the method, under the illumination condition, bis (pinacolato) diboron, alkene and aryl cyanide are used as raw materials, and efficient and green synthesis of organic boride is achieved. Under the illumination condition, the addition of the bis (pinacolato) diboron / alkali complex and olefin is realized through the oxidation of the photocatalyst, and meanwhile, the aryl cyanide is reduced into anion free radicals by the generated photocatalyst in a reduction state. And finally, coupling the produced olefin boronized intermediate free radical with the aryl cyanide anion free radical to generate the olefin 1, 2-boron arylation product. According to the invention, cheap raw materials are used for preparing the organic boride with potential biological activity under the photocatalytic condition, and the method has the value of developing the organic boride capable of being used for industrial synthesis.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis of organic boron compounds, and in particular to a synthesis method for photocatalytic olefin boroarylation. Background Art

[0002] Organoboron compounds are important active groups that are widely found in drug molecules, organic synthesis, and functional materials research. It is worth mentioning that using organoboron compounds as raw materials, a variety of different carbon-carbon bonds can be constructed through Suzuki coupling reactions. At the same time, the boron functional group can also be converted into a variety of different functional groups such as hydroxyl and halogen. Therefore, the development of new methods for the synthesis of organoboron compounds has always been a hot topic in organic synthesis research.

[0003] Photocatalytic synthesis is an important organic synthesis method with advantages such as mild conditions, high tolerance to functional groups, and a wide range of substrate applications. Photocatalytic selective synthesis of highly functional organic boron compounds using cheap and readily available biboronic acid pinacol esters, olefins, and aromatic cyanides as raw materials is an atomic step-economical, green, and efficient synthesis strategy. However, it is usually difficult to regulate the selectivity of three-component reactions, and in the past it often relied on transition metal-catalyzed coupling processes. However, the selectivity of the reaction is difficult to regulate, and is usually accompanied by the generation of a variety of by-products. It also has shortcomings such as low functional group compatibility and harsh conditions, which often limit the scope of application of the reaction.

[0004] As a green synthesis method, photocatalytic reaction is expected to overcome the shortcomings brought by traditional transition metals. Therefore, it is of great practical significance to develop new methods for the synthesis of organic borides with mild conditions and simple operation. Based on the photocatalytic redox single electron transfer strategy, it is expected to achieve multi-component reactions under mild conditions, which can be an effective way to synthesize highly functional organic borides. In the past, the borylation reaction of olefins was mainly achieved based on the catalysis of transition metals such as nickel and palladium, but the synthesis strategy of arylboration of olefins based on photocatalysis has not been reported. Considering that the synthesis of organic borides mainly relied on transition metal catalysis in the past, although the efficiency was high, it did not meet the requirements of the development of modern green chemical industry, and it was difficult to achieve large-scale industrial application.

[0005] A greater breakthrough has been achieved in the synthesis of organic boron compounds with diverse structures through the photocatalytic synthesis of three components: biboric acid pinacol ester, olefin and aryl cyanide. In addition, based on this, it is very necessary to provide a new method for the preparation of photocatalytic organic boron. Summary of the invention

[0006] The purpose of the present invention is to provide a synthesis method for photocatalytic olefin boroarylation, which is used for the synthesis of functional organic boron compounds, aiming to solve the problems of traditional organic boron compound synthesis routes, such as dependence on transition metals, low compatibility, narrow application range, and single product structure.

[0007] The synthesis method of photocatalytic olefin boroarylation provided by the present invention comprises the following steps:

[0008] Add biboric acid pinacol ester, olefin, aryl cyanide, photocatalyst and base into an organic solvent and react under light. The reaction formula is as follows:

[0009]

[0010] In the formula, R1 is selected from aryl or substituted aryl, and the substituent is one of methyl, ethyl or halogen; R2 is selected from one of hydrogen, methyl or ethyl; R3 is selected from cyano; X is N or C; Bpin is pinacol borane group.

[0011] The present invention utilizes photocatalytic oxidation of pinacol diboric acid ester, base and olefin to generate olefin-borated alkyl radicals. At the same time, the reduced state of the photocatalyst reduces aryl cyanide to generate aryl anion radicals, and the generated olefin-borated alkyl radicals and aryl cyanide anion radicals couple to generate the target organic boron compound after undergoing a decyanation process.

[0012] Preferably, R1 is selected from aryl or substituted aryl, and the substituent is one of methyl, ethyl or halogen; R2 is selected from one of hydrogen, methyl or ethyl; R3 is selected from cyano; X is N or C; Bpin is pinacol boryl.

[0013] Preferably, the photocatalyst is selected from tris(2-phenylpyridine)iridium,

[0014] Preferably, the base is selected from one of potassium methoxide, sodium ethoxide, lithium tert-butoxide or potassium tert-butoxide.

[0015] Preferably, the light source in the reaction is a blue light source of 450 to 455 nm, and the power of the light source is 8 to 40 watts.

[0016] Preferably, the boron reagent is selected from biboric acid pinacol ester (abbreviated as B2pin2).

[0017] Preferably, the olefin is selected from styrene or α-methyl substituted styrene, and the aryl cyanide is selected from at least one of tetracyanopyridine and 1,4-phenylenedicyanide.

[0018] Preferably, the organic solvent is selected from at least one of tetrahydrofuran and ethylene glycol dimethyl ether.

[0019] Preferably, the molar ratio of the aryl cyanide, the biboric acid pinacol ester, the olefin, the photocatalyst and the base is 1:1-2:1-2:0.001-0.05:1-2.

[0020] Preferably, the reaction temperature is 20-30° C., the reaction time is 20-48 hours, and the reaction is carried out under the protection of an inert gas.

[0021] Preferably, the organic boron compound has the structural formula of any of the following compounds:

[0022]

[0023] In the above technical scheme, diboronic acid pinacol ester (B2pin2), olefin, aromatic cyanide, photocatalyst and base are used as starting materials to react and synthesize organic boron compound, and this method is further used in the post-modification of the synthesis of functional organic boron compound molecules with potential activity.

[0024] The present invention uses biboric acid pinacol ester (B2pin2), olefin, aryl cyanide, photocatalyst and base as starting materials to react and obtain an organic boron compound. The preparation method utilizes photocatalytic oxidation of biboric acid pinacol ester, base and olefin to generate alkyl radicals of olefin boronation. At the same time, the reduced state of the photocatalyst reduces the aryl cyanide to generate an aryl anion radical, and the generated alkyl radical of olefin boronation and the aryl cyanide anion radical are coupled to generate the target organic boron compound after undergoing a decyanation process. The reaction is compatible with a variety of functional groups and can be used for post-modification transformation of functional organic molecules, and has the value of developing a new method for industrial synthesis of organic boron compound functional molecules.

[0025] Compared with the related art, the synthesis method of photocatalytic olefin borylation provided by the present invention has the following beneficial effects:

[0026] The invention solves the shortcomings of traditional synthesis routes, such as dependence on transition metals, low compatibility, narrow application range, and single product structure. The method has mild reaction conditions and is easy to realize industrial-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The following is the reaction scheme of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0029] The present invention relates to the synthesis of the following compounds:

[0030]

[0031] Embodiment 1, structural formula is:

[0032]

[0033] Its synthesis method is:

[0034] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 4-tert-butylstyrene (64.1 mg, 0.4 mmol, 2.0 equiv.), biboronic acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 47.5 mg of Example 1 compound with a yield of 61%.

[0035] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.59-7.50(m,2H),7.40-7.36(m,2H),7.30-7.26(m,2H),7.16-7.12(m,2H ),4.28(t,J=8.5Hz,1H),1.60-1.55(d,J=7.8Hz,2H),1.27(s,9H),1.05(s,6H),1.03(s,6H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ152.5,149.4,142.0,132.2,128.6,127.3,125.4,119.2,109.7,83.4,46.3,34.4,31.4,24.7,24.6,19.0ppm. 11 B NMR (128MHz, CDCl3) δ 32.8ppm.

[0036] Embodiment 2, structural formula is:

[0037]

[0038] Its synthesis method is:

[0039] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 4-methylstyrene (47.3 mg, 0.4 mmol, 2.0 equiv.), bipyridine (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tris(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 41.7 mg of Example 2 compound with a yield of 60%.

[0040] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.56-7.49(m,2H),7.37-7.34(m,2H),7.12-7.05(m,4 H), 4.28 (t, J = 8.4Hz, 1H), 2.28 (s, 3H), 1.58-1.54 (m, 2H), 1.06 (s, 12H) ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ152.6,142.1,136.1,132.2,129.3,128.5,127.5,119.2,109.7,83.4,46.3,24.7,21.0,19.0ppm. 11 B NMR (128MHz, CDCl3) δ 30.6ppm.

[0041] Embodiment 3, structural formula is:

[0042]

[0043] Its synthesis method is:

[0044] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 4-methoxystyrene (53.7 mg, 0.4 mmol, 2.0 equiv.), bipyridoboric acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tris(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 40 mg of Example 3 compound in a yield of 55%.

[0045] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.57-7.50(m,2H),7.36-7.33(m,2H),7.15-7.11(m,2H),6.83- 6.79(m,2H),4.28(t,J=8.4Hz,1H),3.76(s,3H),1.58-1.51(m,2H),1.07(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ158.2,152.8,137.2,132.2,128.6,128.4,119.2,113.9,109.7,83.4,55.3,45.8,24.6,19.1ppm. 11 B NMR (128MHz, CDCl3) δ 34.5ppm.

[0046] Embodiment 4, structural formula is:

[0047]

[0048] Its synthesis method is:

[0049] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 4-chlorostyrene (55.4 mg, 0.4 mmol, 2.0 equiv.), biboronic acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 46.3 mg of Example 4 compound with a yield of 63%.

[0050] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.60-7.51(m,2H),7.34-7.31(m,2H),7.26-7.21(m,2H) ,7.16-7.13(m,2H),4.29(t,J=8.3Hz,1H),1.56-1.52(m,2H),1.07(s,12H)ppm. 13 C{ 1H}NMR (100MHz, CDCl3): δ151.7,143.5,132.3,129.1,129.0,128.7,128.5,119.0,110.1,83.5,46.0,24.7,18.9ppm. 11 B NMR (128MHz, CDCl3) δ 33.1ppm.

[0051] Embodiment 5, structural formula is:

[0052]

[0053] Its synthesis method is:

[0054] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), α-methylstyrene (47.3 mg, 0.4 mmol, 2.0 equiv.), biboronic acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 54.1 mg of Example 5 compound with a yield of 78%.

[0055] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.59-7.51(m,2H),7.38-7.35(m,2H),7.30-7.25(m ,2H),7.23-7.17(m,3H),1.81(s,3H),1.75-1.70(m,2H),1.03(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ157.0,149.8,131.7,128.1,128.0,127.0,126.1,119.2,109.3,83.1,45.0,29.7,26.0,24.6ppm. 11 B NMR (128MHz, CDCl3) δ 32.4ppm.

[0056] Embodiment 6, structural formula is:

[0057]

[0058] Its synthesis method is:

[0059] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 1-methyl-4-(1-methylvinyl)benzene (52.8 mg, 0.4 mmol, 2.0 equiv.), biboric acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 52.0 mg of Example 6 compound with a yield of 72%.

[0060] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.56-7.48(m,2H),7.36-7.33(m,2H),7.07(s,4H),2.30(s,3H),1.78(s,3H),1.69(s,1H),1.01(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ157.1,147.0,135.5,131.7,128.8,128.0,126.8,119.2,109.2,83.0,44.6,29.7,26.1,24.6,20.9ppm. 11 B NMR (128MHz, CDCl3) δ 32.8ppm.

[0061] Embodiment 7, structural formula is:

[0062]

[0063] Its synthesis method is:

[0064] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 5-benzo[d][1,3]dioxolane (64.8 mg, 0.4 mmol, 2.0 equiv.), biboronic acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 59.4 mg of Example 7 compound with a yield of 76%.

[0065] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.57-7.49(m,2H),7.36-7.33(m,2H),6.72-6.66(m,2H ),6.63-6.61(m,1H),5.90(s,2H),1.75(s,3H),1.65(s,2H),1.03(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ157.0,147.5,145.7,144.1,131.8,127.9,119.9,119.2,109.4,108.1,107.6,101.0,83.1,44.8,29.9,26.5,24.7ppm. 11 B NMR (128MHz, CDCl3) δ 33.4ppm.

[0066] Embodiment 8, structural formula is:

[0067]

[0068] Its synthesis method is:

[0069] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), α-cyclopropylstyrene (57.6 mg, 0.4 mmol, 2.0 equiv.), biboric acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 43.3 mg of Example 8 compound in a yield of 58%.

[0070] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.73-7.64(m,2H),7.58-7.55(m,2H),7.40-7.35(m,2H),7.33-7 .26(m,3H),2.08-1.98(m,3H),1.11(s,12H),0.69-0.61(m,2H),0.09--0.05(m,2H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ154.6,146.4,131.2,129.7,128.9,127.5,126.2,119.3,109.5,83.0,48.8,24.6,24.5,19.8,1.9,1.5ppm. 11 B NMR (128 MHz, CDCl3) δ 33.0 ppm.

[0071] Embodiment 9, structural formula is:

[0072]

[0073] Its synthesis method is:

[0074] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), α-cyclobutylstyrene (63.3 mg, 0.4 mmol, 2.0 equiv.), biboric acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 56.5 mg of Example 9 compound with a yield of 73%.

[0075] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ7.53-7.46(m,2H),7.25-7.19(m,4H),7.17-7.13(m,1H),7.07-7.04(m,2H),3.55-3 .48(m,1H),1.96-1.89(m,2H),1.77-1.61(m,2H),1.59I1.50(m,3H),1.34I1.25(m,1H),0.94(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ154.7,147.2,131.1,129.8,128.9,127.6,126.0,119.3,109.3,82.9,51.0,42.3,24.8,24.6,22.0,17.4ppm. 11 B NMR (128MHz, CDCl3) δ 32.2ppm.

[0076] Embodiment 10, structural formula is:

[0077]

[0078] Its synthesis method is:

[0079] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), 9-ethyl-2-(propyl-1-en-2-yl)-9H-carbazole (63.3 mg, 0.4 mmol, 2.0 equiv.), biboric acid pinacol ester (B2pin2, 0.3 mmol, 76.2 mg, 1.5 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 63.1 mg of Example 8 compound with a yield of 68%.

[0080] Its structure was confirmed by NMR examination; 1 H NMR (400MHz, CDCl3): δ8.08I8.05(m,2H),7.78(s,1H),7.55I7.52(m,2H),7.43-7.39(m,4H),7.23I7.17( m,2H),4.34(d,J=7.2Hz,2H),1.93(s,3H),1.85(d,J=9.6Hz,2H),1.42(d,J=7.2Hz,3H),0.99(s,12H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3): δ158.0,140.5,138.3,132.8,131.7,128.1,125.8,125.6,123.1,122.4 ,120.3,119.4,118.8,118.1,109.1,108.6,108.3,83.0,45.0,37.6,30.3,27.0,24.7,13.9ppm. 11 BNMR (128MHz, CDCl3) δ 34.0ppm. Example 11

[0081] Based on Example 8, the photocatalyst is changed and the synthesis method is as follows:

[0082] Take 1,4-phenylenedicyanide (25.5 mg, 0.2 mmol, 1.0 equiv.), α-cyclobutylstyrene (63.3 mg, 0.4 mmol, 2.0 equiv.), biboronic acid pinacol ester (B2pin2, 0.4 mmol, 101.57 mg, 2 equiv.), tri(2-phenylpyridine)iridium (2 mol%, 0.004 mmol), potassium phosphate (21 mg, 0.3 mmol, 1.5 equiv.), anhydrous tetrahydrofuran (1 mL), under nitrogen protection, seal, irradiate with blue light (wavelength 455 nm, power 40 W), react at room temperature for 24 h, cool, filter, recover the solvent under reduced pressure, and separate by column chromatography to obtain 52.6 mg of Example 8 compound with a yield of 68%.

[0083] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for synthesizing photocatalytic olefin boroarylation, characterized in that: The following steps are involved: Boric acid pinacol ester (B2pin2), olefin, aryl cyanide, photocatalyst and base are added to an organic solvent and reacted under light. The reaction formula is as follows: In the formula, R1 is selected from aryl or substituted aryl, and the substituent is one of methyl, ethyl or halogen; R2 is selected from one of hydrogen, methyl or ethyl; R3 is selected from cyano; X is N or C; Bpin is pinacol borane group.

2. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The aryl cyanide is selected from tetracyanopyridine or 1-4-phenylenedicyanide.

3. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The photocatalyst is selected from tris(2-phenylpyridine)iridium, and the boron reagent is selected from biboric acid pinacol ester (abbreviated as B2pin2).

4. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The base is selected from one of potassium methoxide, sodium ethoxide, lithium tert-butoxide or potassium tert-butoxide.

5. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The light source in the reaction is a blue light source of 450 to 455 nm, and the power of the light source is 8 to 40 watts.

6. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The olefin is selected from styrene or α-methyl substituted styrene, and the aryl cyanide is selected from at least one of tetracyanopyridine and 1,4-phenylenedicyanide.

7. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The organic solvent is selected from at least one of tetrahydrofuran and ethylene glycol dimethyl ether.

8. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The molar ratio of the aryl cyanide, the biboric acid pinacol ester, the olefin, the photocatalyst and the base is 1:1-2:1-2:0.001-0.05:1-2.

9. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The reaction temperature is 20-30° C., the reaction time is 20-48 hours, and the reaction is carried out under the protection of an inert gas.

10. The synthesis method of photocatalytic olefin borylation according to claim 1, characterized in that: The organic boron compound has the structural formula of any of the following compounds:

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