Method for synthesizing alpha, beta-unsaturated imine compound

Abstract

The invention provides a method for synthesizing an alpha, beta-unsaturated imine compound, and belongs to the field of organic synthesis and fine chemicals. According to the method, olefin and nitrone are used as initial raw materials, carbene copper is used as a catalyst, and the alpha, beta-unsaturated imine compound is efficiently synthesized through a one-pot two-step method. According to the method, commercially available carbene copper is used as a catalyst, olefin and nitrone which are low in price and easy to obtain are used as raw materials, operation is easy and convenient, reaction conditions are mild, substrate applicability is wide, and good regioselectivity is achieved. The method disclosed by the invention has important significance in the fields of medicines, materials, fine chemical engineering and the like.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing α,β-unsaturated imine compounds, belonging to the fields of organic synthesis and fine chemicals. Background Art

[0002] Due to the synergistic effect of the carbon-carbon double bond and the carbon-nitrogen double bond, α,β-unsaturated imines have become a class of highly valuable synthons in synthetic chemistry. They can be transformed into other complex nitrogen-containing compounds through various reaction pathways and are widely used in the synthesis of natural products and drug molecules. For example, in the functionalization reaction of drug molecules, the high reactivity of α,β-unsaturated imines supports reactions such as Michael addition and Diels-Alder cyclization, which are used to construct complex chiral centers or cyclic structures, such as the preparation of intermediates for anti-tumor and antiviral drugs and the modification of bioactive molecules. At the same time, through late-stage functionalization, groups such as amino groups and carbonyl groups can be introduced for the synthesis of polypeptides or amino acid analogs.

[0003] The traditional method for synthesizing α,β-unsaturated imines is through the condensation of a,β-unsaturated aldehydes or ketones with amine compounds. This method usually requires relatively complex precursors and a multi-step conversion process, which is cumbersome and has low efficiency. Some synthetic methods also require extreme conditions (such as ultra-low temperature, high pressure, or strong oxidants), with complex operations and high energy consumption. For example, the multi-component tandem reaction method of aryl sulfoxides requires stepwise reactions at -55°C to -95°C, which places strict requirements on equipment and technology. In addition, the early dehydrogenation method requires high temperature or strong oxidation conditions, resulting in poor functional group tolerance and limiting the substrate scope. Some highly efficient syntheses often rely on noble metal catalysts (such as palladium) or chiral catalysts, leading to high costs. For example, although the palladium-catalyzed dehydrogenation method is mild and efficient, the use of noble metals limits its large-scale application.

[0004] In recent years, the copper-catalyzed functionalization reaction of olefins has attracted much attention. By introducing functional groups onto the double bond, this reaction can rapidly construct compounds with complex structures and has the advantages of mild reaction conditions, good substrate generality, and high stereoselectivity, and has become a research hotspot in the field of organic chemistry. Olefins have diverse structures, wide sources, and are easy to obtain, and have important application values in the fields of chemical engineering, materials science, and medicine. On the other hand, nitrone compounds have unique chemical structures and reactivities, and the characteristics of being commercially available or easy to synthesize make them key intermediates in organic synthesis and drug research and development.

[0005] In the present invention, we used olefins and nitrones as starting materials, and carbene copper as a catalyst to efficiently synthesize α,β-unsaturated imine compounds via a one-pot two-step method. In the synthesis, nitrones were used as electrophiles to capture the alkyl copper generated from olefins; subsequently, under the action of oxygen, the intermediate was further transformed to prepare α,β-unsaturated imine compounds. The olefin and nitrone raw materials used in the present invention are cheap and easily available, carbene copper is commercially available, the method is easy to operate, the reaction conditions are mild, the substrate applicability is wide, and it has good regioselectivity. Summary of the Invention

[0006] The object of the present invention is to provide a method for synthesizing α,β-unsaturated imine compounds: using olefins and nitrones as reaction raw materials and carbene copper as a catalyst to synthesize α,β-unsaturated imine compounds via a one-pot two-step method.

[0007] To achieve the above object of the invention, the present invention provides a method for synthesizing α,β-unsaturated imine compounds, and its synthetic route is as follows:

[0008]

[0009] The present invention provides a method for synthesizing α,β-unsaturated imine compounds, and its steps are as follows:

[0010] Add carbene copper catalyst, bis(pinacolato)diboron, base and the nitrone shown in General Formula 2 into a dry Schlenk reaction tube equipped with a magnetic stirrer. Use a Schlenk double manifold to evacuate and introduce argon three times repeatedly. Under the state of introducing argon, add a solvent, stir for 10 minutes, then add the olefin shown in General Formula 1, seal the reaction system, control the reaction system temperature at 25-35 °C, stir and react for 36-48 hours, then introduce oxygen, heat to 60-90 °C, stir for 4-6 hours, cool to room temperature, add ethyl acetate to quench, filter with a basic silica gel column, add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and perform column chromatography separation with a basic silica gel column to obtain the α,β-unsaturated imine compound shown in General Formula 3;

[0011] Wherein Ar in General Formula 1, General Formula 2 and General Formula 3 1 and Ar 2 are selected from aryl groups; the carbene copper catalyst is selected from one of IMesCuCl, IPrCuCl, SIMesCuCl or SIPrCuCl; the base is selected from sodium tert-butoxide, potassium tert-butoxide or lithium tert-butoxide; the solvent is selected from one of toluene, n-hexane, 1,4-dioxane or tetrahydrofuran.

[0012] In the steps of the above method, the molar ratio of the amounts used of olefin 1:nitrone 2:bis(pinacolato)diboron:base:carbene copper is 1.0:3.0-4.0:3.0-4.0:3.0-4.0:0.1-0.2. Detailed implementation mode

[0013] The following implementation examples will help to understand the present invention, but do not limit the content of the present invention.

[0014] Example 1: Synthesis of N,1,2-triphenylprop-2-en-1-imine

[0015]

[0016] Add 15 mg (0.03 mmol) of carbene copper(I) chloride IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide and 177 mg (0.9 mmol) of N,1-diphenylmethanimine oxide into a dry Schlenk reaction tube equipped with a magnetic stirrer. Use a Schlenk double manifold to evacuate and then introduce argon, repeating this three times. Under the condition of argon atmosphere, add 2 mL of toluene. After stirring for 10 minutes, add 35 μL (0.3 mmol) of styrene. Seal the reaction system, control the reaction temperature at 25 °C, stir the reaction for 36 hours, then introduce oxygen, heat to 80 °C, stir for 4 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column. Add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and separate by basic silica gel column chromatography to obtain N,1,2-triphenylprop-2-en-1-imine with a yield of 78%; 1 H NMR (500 MHz, CDCl 3 ) δ 8.01 - 7.95 (m, 2H), 7.47 - 7.38 (m, 3H), 7.28 - 7.19 (m, 5H), 7.13 (t, J = 7.8 Hz, 2H), 6.93 (t, J = 7.4 Hz, 1H), 6.76 (d, J = 7.5 Hz, 2H), 5.87 (s, 1H), 5.17 (s, 1H); 13 C NMR (126 MHz, CDCl 3 ) δ 143.91, 138.39, 137.81, 130.84, 128.75, 128.47, 128.41, 128.27, 128.02, 126.14, 123.34, 119.79, 117.67; HRMS (ESI) m / z calculated for C 21 H 18 N [M+H] + : 284.14338, found 284.1425.

[0017] Example 2: Synthesis of 2-(4-phenyl)phenyl-N,1-diphenylprop-2-en-1-imine

[0018]

[0019] 24 mg (0.06 mmol) of carbene copper(I) chloride IMesCuCl, 305 mg (1.2 mmol) of bis(pinacolato)diboron, 115 mg (1.2 mmol) of sodium tert-butoxide, and 236 mg (1.2 mmol) of N,1-diphenylmethanimine oxide were added to a dry Schlenk reaction tube equipped with a magnetic stir bar. The tube was evacuated using a Schlenk double manifold and then purged with argon three times. Under an argon atmosphere, 2.0 mL of 1,4-dioxane was added, and the mixture was stirred for 10 minutes. Then, 54 mg (0.3 mmol) of 4-phenylstyrene was added, and the reaction system was sealed. The temperature of the reaction system was controlled at 30 °C, and the mixture was stirred for 48 hours. Then, oxygen was introduced, and the temperature was raised to 80 °C, and the mixture was stirred for 4 hours. After cooling to room temperature, the reaction was quenched with ethyl acetate and filtered through a basic silica gel column. Phenylhydrazine was added to the filtrate, and the mixture was stirred for 30 minutes. The reaction solution was concentrated and separated by basic silica gel column chromatography to obtain 2-(4-phenyl)phenyl-N,1-diphenylprop-2-en-1-imine in a yield of 66%; 1 H NMR (500 MHz, CDCl 3 ) δ 8.07 - 7.93 (m, 2H), 7.54 (d, J = 7.7 Hz, 2H), 7.43 (dt, J = 15.4, 8.0 Hz, 7H), 7.36 - 7.29 (m, 3H), 7.15 (t, J = 7.8 Hz, 2H), 6.94 (t, J = 7.4 Hz, 1H), 6.79 (d, J = 7.8 Hz, 2H), 5.91 (s, 1H), 5.17 (s, 1H); 13 C NMR (126 MHz, CDCl 3 ) δ 168.18, 151.26, 143.49, 140.76, 140.35, 138.41, 136.71, 130.91, 128.82, 128.77, 128.50, 128.38, 127.50, 127.18, 126.93, 126.59, 123.42, 119.83, 117.43; HRMS (ESI) m / z calculated for C 27 H 21 NNa [M+Na] + : 382.15662, found 382.1557.

[0020] Example 3: Synthesis of 2-(4-methylphenyl)-N,1-diphenylprop-2-en-1-imine

[0021]

[0022] 30 mg (0.06 mmol) of SIPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 101 mg (0.9 mmol) of potassium tert-butoxide and 177 mg (0.9 mmol) of N,1-diphenylmethanimine oxide were added to a dry Schlenk reaction tube equipped with a magnetic stir bar. The tube was evacuated using a Schlenk double manifold and then purged with argon three times. Under an argon atmosphere, 2 mL of n-hexane was added. After stirring for 10 minutes, 40 μL (0.3 mmol) of 4-methylstyrene was added. The reaction system was sealed and the temperature was controlled at 35 °C. After stirring for 48 hours, oxygen was introduced and the temperature was heated to 70 °C. Stirring was continued for 5 hours. The reaction mixture was cooled to room temperature and quenched with ethyl acetate. The mixture was filtered through a basic silica gel column. Phenylhydrazine was added to the filtrate and stirred for 30 minutes. The reaction solution was concentrated and separated by basic silica gel column chromatography to obtain 2-(4-methylphenyl)-N,1-diphenylprop-2-en-1-imine in a yield of 65%; 1 H NMR (500 MHz, CDCl 3 ) δ 8.00 - 7.94 (m, 2H), 7.44 - 7.35 (m, 3H), 7.20 - 7.11 (m, 5H), 7.03 (d, J = 8.0 Hz, 2H), 6.94 (t, J = 7.4 Hz, 1H), 6.77 (d, J = 7.7 Hz, 2H), 5.82 (s, 1H), 5.08 (s, 1H), 2.28 (s, 3H); 13 C NMR (126 MHz, CDCl 3 ) 6 168.32, 151.28, 143.64, 138.44, 137.99, 134.92, 130.75, 129.24, 128.70, 128.40, 128.31, 126.03, 123.30, 119.79, 116.44, 21.16; HRMS (ESI) m / z calculated C 22 H 20 N [M+H] + : 298.15903, found 298.1590.

[0023] Example 4: Synthesis of 2-(4-methoxyphenyl)-N,1-diphenylprop-2-en-1-imine

[0024]

[0025] To a dry Schlenk reaction tube equipped with a magnetic stir bar, add 15 mg (0.03 mmol) of IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide, and 177 mg (0.9 mmol) of N,1-diphenylmethanimine oxide. Use a Schlenk double manifold to evacuate the air and then introduce argon gas three times repeatedly. Under the condition of argon gas introduction, add 2 mL of toluene. After stirring for 10 minutes, add 40 μL (0.3 mmol) of 4-methoxystyrene. Seal the reaction system, control the reaction system temperature at 30 °C, stir and react for 48 hours, then introduce oxygen, heat to 90 °C, stir for 4 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column, add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and perform column chromatography separation on a basic silica gel column to obtain 2-(4-methoxyphenyl)-N,1-diphenylprop-2-en-1-imine with a yield of 54%; 1 H NMR(500MHz,CDCl 3 )δ7.97(d,J=7.5Hz,2H),7.40(dt,J=14.5,7.0Hz,3H),7.23-7.18(m,2H),7.14(t,J=7.7Hz,2H),6.93(t,J=7.4Hz,1H),6.75(dd,J=14.5,8.2Hz,4H),5.74(s,1H),5.03(s,1H),3.73(s,3H); 13 C NMR(126MHz,CDCl 3 )δ168.41,159.48,151.31,143.21,138.44,130.79,130.41,128.71,128.43,128.32,127.44,123.33,119.77,115.36,113.92,77.33,77.07,76.82,55.23;HRMS(ESI)m / z calculated for C 22 H 20 NO[M+H] + :314.15394,found 314.1540。

[0026] Example 5: Synthesis of N,1-diphenyl-2-(thiophen-2-yl)prop-2-en-1-imine

[0027]

[0028] Add 29 mg (0.06 mmol) of carbene copper(I) chloride IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide, and 177 mg (0.9 mmol) of N,1-diphenylmethanimine oxide to a dry Schlenk reaction tube equipped with a magnetic stir bar. Use a Schlenk double manifold to evacuate the air and introduce argon gas, repeating this process three times. While under an argon atmosphere, add 2 mL of toluene. After stirring for 10 minutes, add 32 μL (0.3 mmol) of 2-vinylthiophene. Seal the reaction system, control the reaction temperature at 30 °C, and stir the reaction for 48 hours. Then introduce oxygen, heat the reaction mixture to 80 °C, and stir for 4 hours. Cool the reaction mixture to room temperature, quench it with ethyl acetate, filter it through a basic silica gel column. Add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and separate it by basic silica gel column chromatography to obtain N,1-diphenyl-2-(thiophen-2-yl)prop-2-en-1-imine with a yield of 36%. 1 H NMR (500 MHz, CDCl 3 ) δ 8.07 - 7.92 (m, 2H), 7.51 - 7.37 (m, 3H), 7.22 - 7.17 (m, 2H), 7.13 (dd, J = 5.1, 1.0 Hz, 1H), 7.03 - 6.95 (m, 1H), 6.86 (dd, J = 5.1, 3.7 Hz, 1H), 6.83 - 6.80 (m, 2H), 6.78 (dd, J = 3.6, 1.0 Hz, 1H), 5.72 (s, 1H), 4.99 (s, 1H); 13 C NMR (126 MHz, CDCl 3 ) δ 166.57, 150.96, 142.18, 138.01, 137.82, 130.95, 128.59, 128.43, 128.38, 127.51, 126.69, 125.16, 123.53, 119.72, 115.90; HRMS (ESI) m / z calculated for C 19 H 16 NO [M + H] + : 290.09980, found 290.0998.

[0029] Example 6: Synthesis of N,1-diphenyl-2-(pyridin-4-yl)prop-2-en-1-imine

[0030]

[0031] Add 29 mg (0.06 mmol) of carbene copper(I) chloride IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide, and 177 mg (0.9 mmol) of N,1-diphenylmethanimine oxide to a dry Schlenk reaction tube equipped with a magnetic stir bar. Use a Schlenk double manifold to evacuate the tube and then introduce argon gas, repeating this process three times. While under an argon atmosphere, add 2 mL of toluene. After stirring for 10 minutes, add 32 μL (0.3 mmol) of 4-vinylpyridine. Seal the reaction system, control the reaction system temperature at 35 °C, stir the reaction for 48 hours, then introduce oxygen, heat to 80 °C, stir for 4 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column, add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and perform column chromatography on a basic silica gel column to obtain N,1-diphenyl-2-(4-pyridyl)prop-2-en-1-imine with a yield of 35%; 1 H NMR(500MHz, CDCl 3 ) δ 8.51 (d, J = 4.7 Hz, 1H), 7.97 (d, J = 7.3 Hz, 2H), 7.56 - 7.49 (m, 1H), 7.45 - 7.34 (m, 3H), 7.20 (d, J = 8.0 Hz, 1H), 7.16 - 7.05 (m, 4H), 6.93 (t, J = 7.3 Hz, 1H), 6.80 (d, J = 7.9 Hz, 2H), 6.34 (s, 1H), 5.36 (s, 1H); 13 C NMR(126MHz, CDCl 3 ) δ 131.30, 130.99, 129.20, 128.68, 128.38, 128.30, 128.12, 128.02, 127.49, 125.13, 120.83, 120.55, 115.51, 77.41, 77.16, 76.91, 69.91, 59.87, 50.81; HRMS(ESI) m / z: calculated for [C 20 H 16 N 2 +H] + 285.1392, found 285.1396.

[0032] Example 7: Synthesis of 1-(4-methylphenyl)-N,2-diphenylprop-2-en-1-imine

[0033]

[0034] Add 24 mg (0.06 mmol) of carbene copper(I) chloride SIMesCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 72 mg (0.9 mmol) of lithium tert-butoxide, and 190 mg (0.9 mmol) of N-phenyl-1-(4-methylphenyl)methanimine oxide to a dry Schlenk reaction tube equipped with a magnetic stir bar. Use a Schlenk double manifold to evacuate the air and then introduce argon gas, repeating this process three times. Under an argon atmosphere, add 2 mL of tetrahydrofuran. After stirring for 10 minutes, add 35 μL (0.3 mmol) of styrene. Seal the reaction system, control the reaction temperature at 35 °C, stir the reaction for 48 hours, then introduce oxygen, heat the reaction mixture to 60 °C, stir for 6 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column, add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and separate by basic silica gel column chromatography to obtain 1-(4-methylphenyl)-N,2-diphenylprop-2-en-1-imine in a yield of 60%; 1 H NMR(500MHz, CDCl 3 )δ7.87(d, J = 8.1Hz, 2H), 7.24(dd, J = 7.7, 1.7Hz, 2H), 7.22 - 7.17(m, 5H), 7.11(t, J = 7.8Hz, 2H), 6.91(t, J = 7.4Hz, 1H), 6.74(d, J = 7.8Hz, 2H), 5.84(s, 1H), 5.14(s, 1H), 2.37(s, 3H); 13 C NMR(126MHz, CDCl 3 )δ168.09, 151.39, 144.04, 141.21, 137.99, 135.84, 129.19, 128.78, 128.49, 128.28, 128.00, 126.18, 123.20, 119.89, 117.41, 21.49; HRMS(ESI) m / z calculated for C 22 H 20 N[M + H] + : 298.1590, found 298.1590.

[0035] Example 8: Synthesis of 1-(4-methoxyphenyl)-N,2-diphenylprop-2-en-1-imine

[0036]

[0037] Add 15 mg (0.03 mmol) of carbene copper(I) chloride IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide, and 205 mg (0.9 mmol) of N-phenyl-1-(4-methoxyphenyl)methanimine oxide to a dry Schlenk reaction tube equipped with a magnetic stir bar. Use a Schlenk double manifold to evacuate the air and then introduce argon gas, repeating this process three times. Under an argon atmosphere, add 2 mL of toluene. After stirring for 10 minutes, add 35 μL (0.3 mmol) of styrene. Seal the reaction system, control the reaction temperature at 30 °C, stir the reaction for 36 hours, then introduce oxygen, heat the reaction mixture to 80 °C, stir for 4 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column. Add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and perform column chromatography on a basic silica gel column to obtain 1-(4-methoxyphenyl)-N,2-diphenylprop-2-en-1-imine with a yield of 42%. 1 H NMR(500MHz,CDCl 3 )δ7.93(d,J=8.8Hz,2H),7.24(d,J=7.3Hz,2H),7.22-7.16(m,3H),7.10(t,J=7.8Hz,2H),6.90(t,J=8.1Hz,3H),6.73(d,J=7.8Hz,2H),5.83(s,1H),5.13(s,1H),3.80(s,3H); 13 C NMR(126MHz,CDCl 3 )6167.49,161.87,151.50,144.05,138.03,131.24,130.53,128.51,128.29,128.02,126.19,123.10,120.01,117.31,113.79,55.40;HRMS(ESI)m / z calculated for C 22 H 20 NO[M+H] + :314.15394,found 314.1538。

[0038] Example 9: Synthesis of N,2-diphenyl-1-(4-trifluoromethylphenyl)prop-2-en-1-imine

[0039]

[0040] Add 15 mg (0.03 mmol) of carbene copper(I) chloride IPrCuCl, 228 mg (0.9 mmol) of bis(pinacolato)diboron, 86 mg (0.9 mmol) of sodium tert-butoxide, and 239 mg (0.9 mmol) of N-phenyl-1-(4-trifluoromethylphenyl)methanimine oxide to a dry Schlenk reaction tube equipped with a magnetic stir bar. Use a Schlenk double manifold to evacuate the air and introduce argon gas three times. While under an argon atmosphere, add 2 mL of toluene. After stirring for 10 minutes, add 35 μL (0.3 mmol) of styrene. Seal the reaction system and control the reaction temperature at 30 °C. Stir the reaction for 36 hours, then introduce oxygen and heat to 80 °C. Stir for 4 hours, cool to room temperature, quench with ethyl acetate, filter through a basic silica gel column. Add phenylhydrazine to the filtrate, stir for 30 minutes, concentrate the reaction solution, and separate by basic silica gel column chromatography to obtain 1-(4-methoxyphenyl)-N,2-diphenylprop-2-en-1-imine in a yield of 33%. 1 H NMR (500 MHz, CDCl 3 ) δ 8.08 (d, J = 8.1 Hz, 2H), 7.65 (d, J = 8.3 Hz, 2H), 7.29 - 7.20 (m, 5H), 7.16 (dd, J = 8.2, 7.6 Hz, 2H), 7.04 - 6.91 (m, 1H), 6.78 (dd, J = 8.4, 1.0 Hz, 2H), 5.91 (s, 1H), 5.18 (s, 1H); 13 C NMR (126 MHz, CDCl 3 ) δ 166.82, 150.67, 143.44, 141.59, 137.27, 128.98, 128.65, 128.40, 128.32, 126.06, 125.38, 125.35, 123.81, 119.60, 118.09; HRMS (ESI) m / z calculated for C 22 H 17 F 3 N[M+H] + : 352.13076, found 352.1309.

Claims

1. A method for synthesizing an α,β-unsaturated imine compound, comprising the following steps: A carbene copper catalyst, bis(pinacol)diboron, a base and a nitrone shown in the general formula 2 are added to a dry Schlenk reaction tube equipped with a stirrer, and a Schlenk double-row tube is used to evacuate and introduce argon gas, which is repeated three times. While introducing argon gas, a solvent is added, and after stirring for 10 minutes, an olefin shown in the general formula 1 is added, and the reaction system is sealed. The temperature of the reaction system is controlled at 25 to 35° C., and after stirring for 36 to 48 hours, oxygen is introduced, and the reaction is heated to 60 to 90° C., stirred for 4 to 6 hours, cooled to room temperature, ethyl acetate is added for quenching, and filtered through an alkaline silica gel column. Phenylhydrazine is added to the filtrate, and stirred for 30 minutes. The reaction solution is concentrated, and separated by alkaline silica gel column chromatography to obtain an α, β-unsaturated imine compound shown in the general formula 3; Wherein Ar in Formula 1, Formula 2 and Formula 3 1 and Ar 2 The carbene copper catalyst is selected from one of IMesCuCl, IPrCuCl, SIMesCuCl and SIPrCuCl; the base is selected from sodium tert-butoxide, potassium tert-butoxide or lithium tert-butoxide; the solvent is selected from one of toluene, n-hexane, 1,4-dioxane or tetrahydrofuran.

2. A method for synthesizing an α, β-unsaturated imine compound according to claim 1, characterized in that The molar ratio of olefin 1: nitrone 2: bis(pinacol)diboron: base: carbene copper is 1.0: 3.0-4.0: 3.0-4.0: 3.0-4.0: 0.1-0.2.

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