Catalyst CudppfBH4 and its application in catalytic reduction of α,β-unsaturated amides

Abstract

The present invention discloses a catalyst CudppfBH4 and its application in catalyzing the reduction reaction of α, β-unsaturated amides. The catalyst CudppfBH4 of the present invention is a complex formed by copper acetylacetonate (Cu(acac)2) and 1,1'-bis(diphenylphosphino)ferrocene (dppf) under the reduction of NaBH4, synthesized by a one-pot method with high yield. The catalyst CudppfBH4 of the present invention can effectively reduce electron-deficient alkynes in alkylamides under mild reaction conditions (80°C, atmospheric pressure), thereby highly selectively generating (Z)-α, β-unsaturated amides, with low catalyst usage and applicability to a variety of substrates.

Description

Technical Field

[0001] The invention belongs to the field of organic catalytic synthesis, and particularly relates to a catalyst CudppfBH4 and an application thereof in catalyzing the reduction reaction of α, β-unsaturated amides. Background Art

[0002] In recent years, bimetallic catalysts have found widespread catalytic applications in industrial production processes. Compared with single components, the assembly of multiple functional units has shown excellent performance in improving catalytic performance and simplifying the chemical process of handling complex target molecules. Bimetallic complexes with dual catalytic sites are not only beneficial for catalyzing homogeneous reactions, but can also be used as precursors for the preparation of heterogeneous binuclear catalysts. The simplicity of their structure makes them a robust model for mechanistic studies involving geometric confinement and synergistic effects. As a stable, redox-active and conformationally flexible diphosphine complex, dppf has been used to prepare heterometallic complexes with various transition metals. This makes dppf a good iron source for the preparation of CuFe binuclear complexes. A prominent example is the application of Cu(OAc)2 and dppf in the addition of aromatic aldehydes to arylboronic acids (The Journal of Organic Chemistry, 2009, 74(2):943-945). The synergistic effect of in situ generated metal-dppf complexes is generally considered to be the source of catalytic activity. Despite this, the identification of related metal-dppf intermediates has rarely been reported. While both monodentate and bidentate phosphine-coordinated Cu complexes have received extensive attention, the precise synthesis and crystal structure of Cu-dppf complexes have yet to be reported. This invention synthesizes a Cu-dppf complex with a precise structure, which can be used for efficient catalysis in multiple reactions.

[0003] Semihydrogenation of alkynes to olefins is one of the most important building blocks in natural products, pharmaceuticals, and agrochemicals. Over the years, various methods have been developed to synthesize (Z)-olefins. The most representative method is the Lindlar catalyst (Pd / CaCO3 / Pb / quinoline), which uses H2 as a hydrogen donor under pressurized conditions. In addition, the effects of other hydrogen donors on the synthesis of (Z)-olefins have been explored, such as water (Organic Letters, 2019, 21(5):1412–1416), silanes (Organometallics, 2018, 37(18):3102–3110), and ammonia borane (Green Energy and Environment, 2023, 8(4):948–971), which make it possible to synthesize (Z)-olefins under mild conditions. However, first-row transition metal catalysts, such as Ni, Co, Cu, and Mn, have rarely been developed for the synthesis of (Z)-olefins. The main reason is that they are limited by the substrate scope and stereoselectivity.

[0004] In summary, highly stereoselective and regioselective hemihydrogenation of electron-deficient alkynes is rare. The bimetallic catalytic material CudppfBH4, designed and prepared by us, not only achieves gram-scale product production but also its own gram-scale production, offering high yields and low cost, offering significant economic and environmental advantages. Furthermore, it exhibits high stereoselectivity and regioselectivity in the reduction of alkynyl amides, substantially improving the efficiency of (Z)-olefin synthesis. Summary of the Invention

[0005] To address the problems of the prior art, the present invention provides a catalyst, CudppfBH4, and its use in catalyzing the reduction of α,β-unsaturated amides. The present invention provides a two-step, gram-scale synthesis of CudppfBH4 (dppf: 1,1'-bis(diphenylphosphino)ferrocene) with high yield. The catalyst, CudppfBH4, can effectively reduce electron-deficient alkynes in alkyl amides under mild reaction conditions (80°C, atmospheric pressure), resulting in highly selective (Z)-α,β-unsaturated amides. The catalyst requires minimal catalyst dosage and is suitable for a variety of substrates.

[0006] The catalyst CudppfBH4 of the present invention is composed of a Cu atom, a bis(diphenylphosphino)ferrocene ligand and a BH4 - Ionic composition ( Figure 4 B).

[0007] The catalyst CudppfBH4 of the present invention is synthesized by a one-pot method by reducing a complex formed by copper acetylacetonate (Cu(acac)2) and 1,1'-bis(diphenylphosphino)ferrocene (dppf) with NaBH4. The maximum absorption peak of the catalyst CudppfBH4 in dichloromethane solution is at 441nm ( Figure 4 A).

[0008] Specifically, it is prepared by a method comprising the following steps:

[0009] Cu(acac)2 (0.7 mmol, 0.18 g) was added to a reaction flask containing 12.5 ml of methanol and 37.5 ml of dichloromethane (methanol:dichloromethane = 1:3) with stirring in a 36°C oil bath, yielding a dark blue solution. After 10 minutes, dppf (1.4 mmol, 0.76 g) was added with continued stirring to yield a yellow-brown Cu-dppf complex solution. After 20 minutes of reaction, NaBH4 / H2O (ice) (0.15 g / 3 mL) was added, causing the solution to turn orange-yellow. Stirring was continued for 8 hours. The crude product was filtered, and the retained solution was rotary evaporated to yield the crude product. The product was washed three times with n-hexane to yield a yellow precipitate. Finally, crystallization from ethanol and n-hexane yielded crystals.

[0010] The catalyst of the present invention has a yield of up to 80%, mild synthesis conditions, bimetallic synergistic effect and reduction performance, and is widely used in the field of catalysis.

[0011] The invention discloses an application of the catalyst CudppfBH4 in catalyzing the reduction reaction of α, β-unsaturated amides.

[0012] The specific steps include:

[0013] Under a nitrogen atmosphere, CudppfBH4 (0.125 mmol, 50 mol%), acetylamide (0.25 mmol), triethylamine (0.625 mmol) and THF (2 mL) were added to a Schlenk tube and stirred at 70 ° C for 24 h. The resulting mixture was centrifuged and rotary evaporated to obtain a crude product, which was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE = 1:4, V / V) to obtain the target product.

[0014] The molar ratio of alkynamide to catalyst CudppfBH4 was 1:0.5.

[0015] The molar ratio of alkynamide to Et3N was 1:2.5.

[0016] The synthetic route is as follows:

[0017]

[0018] R 1 The group is selected from aryl or substituted aryl, wherein the substituents include halogen, methyl or methoxy.

[0019] R 2 、R 3 The group is selected from H, methyl, ethyl or phenyl.

[0020] Further, the substrate alkyne amide is selected from N,N-dimethyl-3-phenylpropioamide, N,N-diethyl-3-phenylpropioamide, N-methyl-N,3-diphenylpropioamide, N,3-diphenylpropioamide, 3-(4-chlorophenyl)-N,N-dimethylpropioamide, 3-(4-methoxyphenyl)-N,N-dimethylpropioamide, 3-(3-chlorophenyl)-N,N-dimethylpropioamide, 3-(4-fluorophenyl)-N,N-dimethylpropioamide, N,N-dimethyl-3-(m-tolyl)propioamide, N,N-diethyl-3-(4-methoxyphenyl)propioamide, N,N-diethyl-3-(4-fluorophenyl)propioamide, 3-(3-bromophenyl)-N,N-diethylpropioamide, and the like.

[0021] The substrate alkyne amide is prepared by conventional methods, comprising the following steps:

[0022] At 0°C, an amine (5 mmol) and phenylpropiolic acid (5 mmol) were added to a 15 mL dichloromethane solution and stirred for 5 minutes. A solution of 4-dimethylaminopyridine (DMAP) (0.5 mmol) and N,N'-dicyclohexylcarboximide (DCC) (7.5 mmol) in dichloromethane (15 mL) was then added. After stirring for 5 minutes, the mixture was transferred to room temperature and reacted for 12 hours. The reaction mixture was filtered through a short section of silica gel powder and then purified by column chromatography.

[0023] The synthetic route is as follows:

[0024]

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The CudppfBH4 catalyst of the present invention can efficiently reduce alkynes on alkynamides to alkenes under mild conditions (70°C) and micropressure (Schlenk tube) to obtain the corresponding acrylamides without any by-products, meeting the requirements of green chemistry.

[0027] 2. The CudppfBH4 catalyst of the present invention has a wide range of applicability to substrates.

[0028] 3. After the CudppfBH4 catalyst reaction, dppf can be recovered as a synthetic raw material, thus achieving recycling.

[0029] 4. The CudppfBH4 catalyst of the present invention can be used for gram-scale experiments and yield gram-scale products.

[0030] 5. The CudppfBH4 catalyst of the present invention can be produced at the gram level and can be synthesized in large quantities. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram and physical picture of the gram-scale synthesis of CudppfBH4.

[0032] Figure 2 This is a schematic diagram of the CudppfBH4 reduction reaction.

[0033] Figure 3 The mass spectrum (a) and H NMR spectrum (b) of CudppfBH4.

[0034] Figure 4 The UV image (A) and single crystal structure (B) of CudppfBH4. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0036] The catalyst CudppfBH4 of the present invention is composed of a Cu atom, a bis(diphenylphosphino)ferrocene ligand and a BH4 - Ionic composition ( Figure 4 B).

[0037] The catalyst CudppfBH4 of the present invention is synthesized by a one-pot method by reducing a complex formed by copper acetylacetonate (Cu(acac)2) and 1,1'-bis(diphenylphosphino)ferrocene (dppf) with NaBH4. The maximum absorption peak of the catalyst CudppfBH4 in dichloromethane solution is at 441nm ( Figure 4 A).

[0038] Specifically, it is prepared by a method comprising the following steps:

[0039] Cu(acac)2 (0.7 mmol, 0.18 g) was added to a reaction flask containing 12.5 ml of methanol and 37.5 ml of dichloromethane (methanol:dichloromethane = 1:3) with stirring in a 36°C oil bath, yielding a dark blue solution. After 10 minutes, dppf (1.4 mmol, 0.76 g) was added with continued stirring to yield a yellow-brown Cu-dppf complex solution. After 20 minutes of reaction, NaBH4 / H2O (ice) (0.15 g / 3 mL) was added, causing the solution to turn orange-yellow. Stirring was continued for 8 hours. The crude product was filtered, and the retained solution was rotary evaporated to yield the crude product. The product was washed three times with n-hexane to yield a yellow precipitate. Finally, crystallization from ethanol and n-hexane yielded crystals.

[0040] Example 1: CudppfBH4 catalyzes the reduction of N,N-dimethyl-3-phenylpropiolamide in tetrahydrofuran solution

[0041]

[0042] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,N-dimethyl-3-phenylpropynamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70 °C for 24 h; the target product N,N-dimethyl-3-phenylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 92% (Z / E=92 / 8).

[0043] 1H NMR(600MHz,Chloroform-d)δ7.35–7.27(m,5H),6.65(d,J=12.7Hz,1H),6.04(d,J=12.6Hz,1H),2.97(s,3H),2.83(s,3H).HRMS(ESI)m / z calcd for C 11 H 13 NO[M+H] + 176.1064,Found 176.1064.

[0044] Example 2: CudppfBH4 catalyzes the reduction of N,N-diethyl-3-phenylpropiolamide in tetrahydrofuran solution

[0045]

[0046] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,N-diethyl-3-phenylpropynamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added sequentially to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h. The target product N,N-diethyl-3-phenylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V) with a conversion rate of 96.7% (Z / E=90 / 10).

[0047] 1 H NMR(600MHz,Chloroform-d)δ7.39(d,J=7.2Hz,2H),7.32–7.21(m,3H),6.58(d,J=12.6Hz,1H),6.05(d ,J=12.6Hz,1H),3.55–3.37(m,2H),3.24(d,J=7.0Hz,2H),1.14(d,J=6.9Hz,3H),0.94(d,J=7.0Hz,3H). 13 C NMR (151MHz, Chloroform-d) δ168.23,135.5,132.68,128.43,128.37,128.3,123.77,42.54,38.89,13.93,12.41.

[0048] Example 3: CudppfBH4 catalyzes the reduction of N-methyl-N,3-diphenylpropynamide in tetrahydrofuran solution

[0049]

[0050] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N-methyl-N, 3-diphenylpropynamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70 ° C for 24 h. After the reaction, the target product N-methyl-N, 3-diphenylpropynamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE = 1:4, V / V), and the conversion rate was 99.30% (Z / E = 91 / 9).

[0051] 1 H NMR(400MHz,Chloroform-d)δ7.48(t,J=7.5Hz,1.5H),7.39(s,2H),7.36–7.32(m,4H),7.28(s,1H),6.97–6 .93(m,1.5H),6.42(d,J=12.5Hz,1H),5.87(d,J=12.5Hz,1H),3.45(s,1.5H),3.36(s,1.5H).HRMS(ESI)m / z calcd for C 16 H 15 NO[M+H] + 238.1226,Found 238.1226.

[0052] Example 4: CudppfBH4 catalyzes the reduction of N,3-diphenylpropynamide in tetrahydrofuran solution

[0053]

[0054] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,3-diphenylpropynamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h; the target product N,3-diphenylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 99.5% (Z / E=90 / 10).

[0055] 1H NMR(400MHz,Chloroform-d)δ7.69(br,1H),7.58(d,J=31.3Hz,2H),7.37–7.32(m,5H),7.29(d,J =7.4Hz,2H),7.09(t,J=7.1Hz,1H),6.93(d,J=12.5Hz,1H),6.12(d,J=12.5Hz,1H).HRMS(ESI)m / z calcd for C 15 H 13 NO[M+H] + 224.1070,Found 224.1070.

[0056] Example 5: CudppfBH4 catalyzes the reduction of 3-(4-chlorophenyl)-N,N-dimethylpropiolamide in tetrahydrofuran solution

[0057]

[0058]

[0059] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of 3-(4-chlorophenyl)-N,N-dimethylpropioamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70 °C for 24 h; the target product 3-(4-chlorophenyl)-N,N-dimethylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 98% (Z / E=92 / 8).

[0060] 1 H NMR(600MHz,Chloroform-d)δ7.29(d,J=2.8Hz,4H),6.59(d,J=12.6Hz,1H),6.07(d,J=12.6Hz,1H),2.98(s,3H),2.85(s,3H).HRMS(ESI)m / z calcd for C 11 H 12 NOCl[M+H] + 210.0681,Found 210.0681.

[0061] Example 6: CudppfBH4 catalyzes the reduction of 3-(3-chlorophenyl)-N,N-dimethylpropiolamide in tetrahydrofuran solution

[0062]

[0063] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of 3-(3-chlorophenyl)-N,N-dimethylpropioamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h; the target product 3-(3-chlorophenyl)-N,N-dimethylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 92% (Z / E=92 / 8).

[0064] 1 H NMR(600MHz,Chloroform-d)δ7.33(s,1H),7.28–7.26(m,3H),6.59(d,J=12.5Hz,1H),6.12(d,J=12.6Hz,1H),3.00(s,3H),2.87(s,3H).HRMS(ESI)m / z calcd forC 11 H 12 NOCl[M+H] + 210.0688.Found 210.0688.

[0065] Example 7: CudppfBH4 catalyzes the reduction of 3-(4-fluorophenyl)-N,N-dimethylpropiolamide in tetrahydrofuran solution

[0066]

[0067] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of 3-(4-fluorophenyl)-N,N-dimethylpropioamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h; the target product 3-(4-fluorophenyl)-N,N-dimethylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 97% (Z / E=98 / 2).

[0068] 1 H NMR(400MHz,Chloroform-d)δ7.41–7.30(m,2H),7.00(t,J=8.6Hz,2H),6.60(d,J= 12.6Hz,1H),6.03(d,J=12.6Hz,1H),2.98(s,3H),2.86(s,3H).HRMS(ESI)m / zcalcd for C 11 H12 NOF[M+H] + 194.0971,Found 194.0971.

[0069] Example 8: CudppfBH4 catalyzes the reduction of 3-(4-methoxyphenyl)-N,N-dimethylpropiolamide in tetrahydrofuran solution

[0070]

[0071] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of 3-(4-methoxyphenyl)-N,N-dimethylpropioamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70 °C for 24 h; the target product 3-(4-methoxyphenyl)-N,N-dimethylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 98% (Z / E=98 / 2).

[0072] 1 H NMR(600MHz,Chloroform-d)δ7.30(d,J=8.4Hz,2H),6.83(d,J=8.4Hz,2H),6.57(d,J=12 .5Hz,1H),5.92(d,J=12.5Hz,1H),3.80(s,3H),2.99(s,3H),2.86(s,3H).HRMS(ESI)m / z calcd for C 12 H 15 NO2[M+H] + 206.1179,Found 206.1179

[0073] Example 9: CudppfBH4 catalyzes the reduction of N,N-dimethyl-3-(m-tolyl)propiolamide in tetrahydrofuran solution

[0074]

[0075] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,N-dimethyl-3-(m-tolyl)propiolamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h. The target product N,N-dimethyl-3-(m-tolyl)acrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V) with a conversion rate of 99.60% (Z / E=98 / 2).

[0076] 1 H NMR(400MHz,Chloroform-d)δ7.23–7.06(m,4H),6.61(d,J=12.5Hz,1H),6.01(d,J=12.5Hz,1H),2.97(s,3H),2.82(s,3H),2.32(s,3H).HRMS(ESI)m / z calcd forC 12 H 15 NO[M+H] + 190.1223,Found 190.1223.

[0077] Example 10: CudppfBH4 catalyzes the reduction of N,N-diethyl-3-(4-methoxyphenyl)propiolamide in tetrahydrofuran solution

[0078]

[0079] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,N-diethyl-3-(4-methoxyphenyl)propiolamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h. After the reaction, the target product N,N-diethyl-3-(4-methoxyphenyl)acrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V) with a conversion rate of 90% (Z / E=97 / 3).

[0080] 1H NMR(600MHz,Chloroform-d)δ7.35(d,J=8.7Hz,2H),6.82(d,J=8.7Hz,2H),6.52(d,J=12.6Hz,1H)5.94(d,J=12.7Hz,1H ),3.79(s,3H),3.47(d,J=7.1Hz,2H),3.28(d,J=7.1Hz,2H),1.18(t,J=7.1Hz,3H),0.99(t,J=7.1Hz,3H).HRMS(ESI)m / z calcdfor C 14 H 19 NO2[M+H] + 234.1492,Found 234.1492.

[0081] Example 11: CudppfBH4 catalyzes the reduction of N,N-diethyl-3-(4-fluorophenyl)propiolamide in tetrahydrofuran solution

[0082]

[0083] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of N,N-diethyl-3-(4-fluorophenyl)propiolamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70°C for 24 h. The target product N,N-diethyl-3-(4-fluorophenyl)acrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V) with a conversion rate of 99.4% (Z / E=96 / 4).

[0084] 1 H NMR(600MHz,Chloroform-d)δ7.45–7.36(m,2H),6.98(t,J=8.7Hz,2H),6.55(d,J=12.6Hz,1H),6.05(d,J=12.6H z,1H),3.46(q,J=7.1Hz,2H),3.27(q,J=7.1Hz,2H),1.16(t,J=7.2Hz,3H),0.98(t,J=7.1Hz,3H).HRMS(ESI)m / z calcd for C 13 H 16 NOF[M+H] + 222.1285,Found 222.1285.

[0085] Example 12: CudppfBH4 catalyzes the reduction of 3-(3-bromophenyl)-N,N-diethylpropiolamide in tetrahydrofuran solution

[0086]

[0087] Under a nitrogen atmosphere, 80 mg of CudppfBH4, 0.25 mmol of 3-(3-bromophenyl)-N,N-diethylpropioamide, 0.625 mmol of triethylamine and 2 mL of tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction flask, the Schlenk was sealed, and the reaction was carried out at 70 °C for 24 h; the target product 3-(3-bromophenyl)-N,N-diethylacrylamide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V), and the conversion rate was 99.30% (Z / E=93 / 7).

[0088] 1 H NMR(600MHz,Chloroform-d)δ7.55(t,J=1.8Hz,1H),7.39(ddd,J=8.0,2.0,1.0Hz,1H),7.33(s,1H),7.18(d,J=7.8Hz,1H),6.52(d ,J=12.7Hz,1H),6.12(d,J=12.7Hz,1H),3.46(d,J=7.1Hz,2H),3.26(d,J=7.1Hz,2H),1.19(t,J=7.1Hz,3H),0.99(t,J=7.1Hz,3H). 13 CNMR(101MHz,Chloroform-d)δ167.60,137.51,131.25,131.12,131.12,129.93,127.05,125.27,122.52,42.61,39.04,14.02,12.54.

Claims

1. Application of the catalyst CudppfBH4 in catalyzing the reduction reaction of α,β-unsaturated amides, characterized by: The structure of the catalyst CudppfBH4 is shown below: 。 2. The use according to claim 1, characterized in that: Under nitrogen atmosphere, CudppfBH4, alkyne amide, triethylamine, and THF were added to a Schlenk tube for reaction. After the reaction, the resulting mixture was centrifuged and rotary evaporated to obtain a crude product, which was then separated by thin-layer chromatography to obtain the target product. The synthetic route is shown below: ； R 1 The group is selected from aryl or substituted aryl, wherein the substituent is halogen, methyl, methoxy; R 2 、R 3 The group is selected from H, methyl, ethyl or phenyl.

3. The use according to claim 2, characterized in that: The molar ratio of alkynamide to catalyst CudppfBH4 was 1:0.

5.

4. The use according to claim 2, characterized in that: The molar ratio of alkynamide to Et3N was 1:2.5.

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