Catalyst CudppfBH4 and application thereof in catalysis of reduction reaction of alpha, beta-unsaturated amide

Abstract

The invention discloses a catalyst CudppfBH4 and an application of the catalyst CudppfBH4 in catalysis of a reduction reaction of alpha, beta-unsaturated amide. The catalyst CudppfBH4 disclosed by the invention is synthesized from a complex formed by copper acetylacetonate (Cu (acac) 2) and 1, 1 '-bis (diphenylphosphine) ferrocene (dppf) through a one-pot method under the reduction of NaBH4, and the yield is high. The catalyst CudppfBH4 can effectively reduce electron-deficient alkyne in alkylamide under mild reaction conditions (80 DEG C and atmospheric pressure), so that the (Z)-alpha, beta-unsaturated amide is generated with high selectivity, and the catalyst is low in dosage and suitable for various substrates.

Description

Technical Field

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

[0002] In recent years, bimetallic catalysts have found widespread catalytic applications in industrial production processes. Compared with individual components, the assembly of multiple functional units has performed well 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 fabrication 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 fabrication 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 the in situ generated metal-dppf complex is generally considered to be the source of the catalytic activity. Despite this, the identification of the relevant metal-dppf intermediates has rarely been reported. Both monodentate phosphine and bidentate phosphine coordinated Cu complexes have received extensive attention, while the precise synthesis and crystal structure of Cu-dppf complexes have not been reported. The present invention synthesizes a Cu-dppf complex with a precise structure, which can be applied to the efficient catalysis of 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, other hydrogen donors have been explored for the synthesis of (Z)-olefins, 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 makes 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 semihydrogenation reactions of electron-deficient alkynes are rare. The bimetallic catalytic material CudppfBH4 designed and prepared by us can achieve gram-scale product preparation while also being able to carry out gram-scale preparation of itself, with high yield and low price, and has certain economic and environmental advantages. In addition, when used in the reduction of alkynyl amides, it has high stereoselectivity and regioselectivity, which essentially improves the synthesis efficiency of (Z)-olefins. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a catalyst CudppfBH4 and its application in catalyzing the reduction reaction of α, β-unsaturated amides. The present invention realizes a two-step gram-scale synthesis method of CudppfBH4 (dppf: 1,1'-bis(diphenylphosphino)ferrocene) with high yield. The catalyst CudppfBH4 of the present invention can effectively reduce electron-deficient alkynes in alkyl amides under mild reaction conditions (80°C, atmospheric pressure), thereby highly selectively generating (Z)-α, β-unsaturated amides, with low catalyst dosage and applicable to a variety of substrates.

[0006] The catalyst CudppfBH4 of the present invention has a structure consisting of a Cu atom, a bis(diphenylphosphinoferrocene) ligand and a BH4 - Ion 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 a dichloromethane solution is at 441nm ( Figure 4 A).

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

[0009] Under the condition of stirring in an oil bath at 36°C, Cu(acac)2 (0.7mmol, 0.18g) was added to a reaction bottle containing 12.5ml methanol and 37.5ml dichloromethane (methanol: dichloromethane = 1:3) to obtain a dark blue solution. After 10 minutes, dppf (1.4mmol, 0.76g) was added under stirring to obtain a yellow-brown Cu-dppf complex solution. After reacting for 20 minutes, NaBH4 / H2O (ice) (0.15g / 3mL) was added, and the solution turned orange-yellow and continued to stir for 8 hours. Filter, retain the solution, and rotary evaporate to obtain a crude product. Wash with n-hexane 3 times to obtain a yellow precipitate. Finally, crystallize with ethanol and n-hexane to obtain 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 catalysis field.

[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 is 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 radical is selected from H, methyl, ethyl or phenyl.

[0020] Further, the substrate alkyne amide is selected from N,N-dimethyl-3-phenylpropiolamide, N,N-diethyl-3-phenylpropiolamide, N-methyl-N,3-diphenylpropiolamide, N,3-diphenylpropiolamide, 3-(4-chlorophenyl)-N,N-dimethylpropiolamide, 3-(4-methoxyphenyl)-N,N-dimethylpropiolamide, 3-(3-chlorophenyl)-N,N-dimethylpropiolamide, 3-(4-fluorophenyl)-N,N-dimethylpropiolamide, N,N-dimethyl-3-(m-tolyl)propiolamide, N,N-diethyl-3-(4-methoxyphenyl)propiolamide, N,N-diethyl-3-(4-fluorophenyl)propiolamide, 3-(3-bromophenyl)-N,N-diethylpropiolamide and the like.

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

[0022] In an environment of 0°C, amine (5mmol) and phenylpropiolic acid (5mmol) were added to 15ml of dichloromethane solution and stirred for 5 minutes, then 4-dimethylaminopyridine (DMAP) (0.5mmol) and N,N'-dicyclohexylcarbocyanine (DCC) (7.5mmol) in dichloromethane (15ml) solution were added, stirred for 5 minutes, and the mixture was transferred to room temperature for reaction for 12 hours. The reaction mixture was filtered through a small 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 the alkyne on the alkyne amide to olefin under mild conditions (70° C.) and micropressure (Schlenk tube) to obtain the corresponding acrylamide without any by-products, thus meeting the requirements of green chemistry.

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

[0028] 3. After the CudppfBH4 catalyst of the present invention reacts, dppf can be recovered as a synthetic raw material, thereby achieving recycling.

[0029] 4. The CudppfBH4 catalyst of the present invention can be used for gram-level experiments and produce gram-level 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 reduction reaction of CudppfBH4.

[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 has a structure consisting of a Cu atom, a bis(diphenylphosphinoferrocene) ligand and a BH4 - Ion 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 a dichloromethane solution is at 441nm ( Figure 4 A).

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

[0039] Under the condition of stirring in an oil bath at 36°C, Cu(acac)2 (0.7mmol, 0.18g) was added to a reaction bottle containing 12.5ml methanol and 37.5ml dichloromethane (methanol: dichloromethane = 1:3) to obtain a dark blue solution. After 10 minutes, dppf (1.4mmol, 0.76g) was added under stirring to obtain a yellow-brown Cu-dppf complex solution. After reacting for 20 minutes, NaBH4 / H2O (ice) (0.15g / 3mL) was added, and the solution turned orange-yellow and continued to stir for 8 hours. Filter, retain the solution, and rotary evaporate to obtain a crude product. Wash with n-hexane 3 times to obtain a yellow precipitate. Finally, crystallize with ethanol and n-hexane to obtain crystals.

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

[0041]

[0042] Under a nitrogen atmosphere, 80 mg CudppfBH4, 0.25 mmol N, N-dimethyl-3-phenylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added into a 10 mL Schlenk reaction bottle in sequence, 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-phenylpropyneamide in tetrahydrofuran solution

[0045]

[0046] Under a nitrogen atmosphere, 80 mg CudppfBH4, 0.25 mmol N, N-diethyl-3-phenylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added to a 10 mL Schlenk reaction bottle in sequence, 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), and the conversion rate was 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 CudppfBH4, 0.25 mmol N-methyl-N, 3-diphenylpropyne amide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added to a 10 mL Schlenk reaction bottle in sequence, 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-diphenylpropyne amide was separated by thin layer chromatography (TLC) on a silica gel plate (EA / PE=1:4, V / V) with a conversion rate of 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-diphenylpropyne amide in tetrahydrofuran solution

[0053]

[0054] Under a nitrogen atmosphere, 80 mg CudppfBH4, 0.25 mmol N, 3-diphenylpropyne amide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added to a 10 mL Schlenk reaction bottle in sequence, 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 CudppfBH4, 0.25 mmol 3-(4-chlorophenyl)-N,N-dimethylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction bottle, 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 CudppfBH4, 0.25 mmol 3-(3-chlorophenyl)-N,N-dimethylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction bottle, 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 CudppfBH4, 0.25 mmol 3-(4-fluorophenyl)-N,N-dimethylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added into a 10 mL Schlenk reaction bottle in sequence, 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 CudppfBH4, 0.25 mmol 3-(4-methoxyphenyl)-N,N-dimethylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added into a 10 mL Schlenk reaction bottle in sequence, 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 CudppfBH4, 0.25 mmol N,N-dimethyl-3-(m-tolyl)propiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction bottle, 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), and the conversion rate was 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 CudppfBH4, 0.25 mmol N, N-diethyl-3-(4-methoxyphenyl) propiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added to a 10 mL Schlenk reaction bottle in sequence, 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), and the conversion rate was 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 CudppfBH4, 0.25 mmol N, N-diethyl-3-(4-fluorophenyl) propiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added to a 10 mL Schlenk reaction bottle in sequence, 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), and the conversion rate was 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 CudppfBH4, 0.25 mmol 3-(3-bromophenyl)-N,N-diethylpropiolamide, 0.625 mmol triethylamine and 2 mL tetrahydrofuran were added in sequence to a 10 mL Schlenk reaction bottle, 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. A catalyst CudppfBH4, characterized in that: The catalyst CudppfBH4 consists of a Cu atom, a bis(diphenylphosphinoferrocene) ligand and a BH4 - Ion composition.

2. The method for preparing the catalyst CudppfBH4 according to claim 1, characterized in that: The catalyst CudppfBH4 is synthesized by a one-pot method from a complex formed by copper acetylacetonate and 1,1'-bis(diphenylphosphino)ferrocene under the reduction of NaBH4.

3. The preparation method according to claim 2, characterized in that The steps include: Under stirring in an oil bath at 36°C, copper acetylacetonate was added to a mixed solvent of methanol and dichloromethane to obtain a dark blue solution, and then 1,1'-bis(diphenylphosphino)ferrocene was added under stirring to obtain a yellow-brown Cu-dppf complex solution. After reacting for 20 minutes, NaBH4 / H2O was added, and the solution turned orange-yellow, and the reaction was continued by stirring. After the reaction was completed, the solution was filtered and retained, and the crude product was obtained by rotary evaporation, which was washed with n-hexane to obtain a yellow precipitate, and finally crystallized with ethanol and n-hexane to obtain crystals.

4. The preparation method according to claim 3, characterized in that: The volume ratio of methanol to dichloromethane is 1:

3.

5. Use of the catalyst CudppfBH4 according to claim 1 in catalyzing the reduction reaction of α, β-unsaturated amides.

6. The use according to claim 5, 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 separated by thin layer chromatography to obtain the target product. The synthetic route is as follows: R 1 The group is selected from aryl or substituted aryl, wherein the substituents include halogen, methyl, methoxy; R 2 , R 3 The radical is selected from H, methyl, ethyl or phenyl.

7. The use according to claim 6, characterized in that: The molar ratio of alkynamide to catalyst CudppfBH4 is 1:0.

5.

8. The use according to claim 6, characterized in that: The molar ratio of alkynamide to Et3N was 1:2.5.

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