Method for deoxidizing and reducing tertiary amide into amine under promotion of visible light

Abstract

The invention belongs to the technical field of organic synthesis, and discloses a method for deoxidizing and reducing tertiary amide into amine under promotion of visible light. The invention develops a method for efficiently deoxidizing and reducing tertiary amide into amine under the catalysis of low-valent tungsten by using HBPin as a hydrogen source, commercially available W (CO) 6 is used as a catalyst, other additives are not used under the irradiation of visible light, TON reaches up to 2000, and the reaction has good functional group tolerance and can be suitable for reduction of aromatic or aliphatic substituted tertiary amide.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for reducing tertiary amide to amine by deoxygenation promoted by visible light. Background Art

[0002] Tungsten is a transition metal that is relatively abundant in nature. Compared with its use in metal materials, it is less used as a catalyst in organic reactions. High-valent tungsten complexes are usually used in olefin and alkyne metathesis reactions, polymerization reactions, and photocatalytic reactions. Low-valent tungsten is increasingly attracting attention in organic catalytic transformations due to its multi-coordination ability, higher Lewis acidity than other transition metals, and lower (but still) redox reaction potential.

[0003] Trost and his collaborators used W(CO)3(CH3CN)3 and 2,2'-bipyridine as catalysts to carry out pioneering work on low-valent tungsten-catalyzed allylic substitution reactions [(a) BMTrost, MHHung, Tungsten-catalyzed allylic alkylations. New avenues for selectivity, J.Am.Chem.Soc.1983,105,7757-7759. (b) BMTrost, MHHung, On the regiochemistry of metal-catalyzed allylicalkylation: a model, J.Am.Chem.Soc.1984,106,6837-6839. (c) BMTrost, GBTometzki, MHHung, Unusual chemoselectivity using difunctional allylicalkylating agents, J.Am.Chem.Soc.1987,109,2176-2177.]. Pfaltz and his co-workers used chiral tungsten complexes in asymmetric allylic alkylation reactions (GCLloyd-Jones, A. Pfaltz, Chiral Phosphanodihydrooxazoles in Asymmetric Catalysis: Tungsten-Catalyzed Allylic Substitution, Angew. Chem. Int. Ed. Engl. 1995, 34, 462-463.). Adams and his collaborators developed a W(CO)5(CH3CN)-catalyzed method for converting vinyl thiolane into 3,6-dihydro-1,2-dithiol, with a turnover number (TON) of up to 2000 (RD Adams, JL Perrin, Catalytic Transformations of Vinylthiiranes by Tungsten Carbonyl Complexes. A New Route to 3,6-Dihydro-1,2-dithiins, J. Am. Chem. Soc. 1999, 121, 3984-3991.). In recent years, several low-valent tungsten catalytic systems have also been developed; however, the catalytic efficiency is average, and the catalyst dosage is usually between 1 and 20%.

[0004] Efficient conversion of amides to amines is a very important transformation, as amines have important applications in agrochemistry, pharmaceuticals, and materials chemistry, and amides are easy to synthesize or obtain from nature. Strong reducing metal hydrogenation reagents, such as LiAlH4, NaBH4, or B2H6, are not ideal for the reduction of amides due to their limited selectivity toward other reducible functional groups. Catalytic hydrogenation of amides with H2 is an ideal approach due to its atom economy. However, current methods often suffer from expensive metal catalysts, high temperature, high pressure conditions, and poor chemoselectivity. Therefore, exploring alternative hydrogen sources other than H2 is a desirable approach to avoid high pressure or temperature. Transfer hydrogenation and hydrosilylation reactions of amides are promising approaches.

[0005] Pinacol borane (HBpin) is a low-cost, air-stable reagent with good tolerance and selectivity for functional groups, making it an ideal hydrogen source for the reduction of amides. The Sadow group reported the first case of the use of To MMethod for the hydroboration and deoxygenation of amides to amines using MgMe as a catalyst (NLLampland, M.Hovey, D.Mukherjee, AD Sadow, Magnesium-Catalyzed Mild Reduction of Tertiary and Secondary Amides to Amines, ACS Catal. 2015, 5, 4219-4226.). The Dub group reported the vanadium-catalyzed deoxygenation reduction of amides using 0.5 mol% catalyst; however, the synthesis of vanadium catalysts is relatively complicated (G.Zhang, J.Wu, S.Zheng, MCNeary, J.Mao, M.Flores, RJTrovitch, PADub, Redox-Noninnocent Ligand-Supported Vanadium Catalysts for the Chemoselective Reduction of C=X(X=O,N)Functionalities, J.Am.Chem.Soc. 2019, 141, 15230-15239.). Subsequently, various catalytic systems involving this conversion have been developed; however, the catalytic efficiency is generally moderate, with the catalyst dosage usually ranging from 0.5 to 10%. For example, the Engle group (R. Hoffmann, BF Beier, ELM uetteries, A.R. Rossi, Seven-coordination. Amolecular orbital exploration of structure, stereochemistry, and reaction dynamics, Inorg. Chem. 1977, 16, 511-522.) and the Song group (H. Song, Y. Xiao, J. Wei, Y. Liu, L. Yang, P. Bai, F. Yang, K. Yu, C. Xu, X. Cai, Low-valent-tungsten catalysis enables hydroboration of esters and nitriles, Chem. Commun. 2024, 60, 5026-5029.) observed the deoxygenation reduction of amides in a tungsten catalytic system; however, the catalytic efficiencies they disclosed were only moderate, at 40% yield and 52% yield, respectively.In addition, the Song group also disclosed the deoxygenative reduction of 1°, 2° and 3° amides catalyzed by in situ generated tungsten clusters, but it required the use of 5 mol% W(MeCN)2(CO)4 as a pre-catalyst (Y.Liu, X.Zhai, L.Yang, X.Cai, F.Yang, C.Xu, H.Song, Deoxygenative Reduction of 1°, 2°and 3°Amides via In SituGenerated Tungsten Cluster Acting as H-Bonding Donor, Org.Lett.2024,26,11067-11072.).

[0006] Therefore, how to efficiently carry out the deoxygenation reduction of amide to amine under mild reaction conditions is an urgent problem that needs to be solved. Summary of the invention

[0007] The object of the present invention is to provide a method for the deoxidation reduction of tertiary amides to amines promoted by visible light, so as to solve the problem of low efficiency of the existing tungsten catalyst system.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a method for the deoxygenation reduction of tertiary amides to amines promoted by visible light, comprising the following steps:

[0010] In a protective gas atmosphere, a tertiary amide compound, pinacol borane, a tungsten catalyst and a solvent are mixed and reacted under the promotion of visible light to obtain an amine compound;

[0011] The structure of the tertiary amide compound is:

[0012] The structure of the amine compound is:

[0013] Among them, the R 1 is one of H, substituted or unsubstituted alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted aromatic heterocycle, substituted or unsubstituted furan, substituted or unsubstituted pyrrole, substituted or unsubstituted thiophene, and substituted or unsubstituted cycloalkyl;

[0014] The R 2 , R 3 R is independently one of an alkyl group, a benzene ring, a benzyl group, or 2 , R 3 Form a ring.

[0015] Preferably, the tungsten catalyst is tungsten hexacarbonyl.

[0016] Preferably, the solvent is one or more of n-hexane, ether, toluene, tetrahydrofuran, acetonitrile, dichloromethane, and 1,4-dioxane.

[0017] Preferably, the molar ratio of the tertiary amide compound, pinacol borane and tungsten catalyst is 0.5-1:1.5-3:0.0005-0.05.

[0018] Preferably, the usage ratio of the tertiary amide compound and the solvent is 0.5-1 mmol:1 mL.

[0019] Preferably, the wavelength of the visible light is 405 nm; the light source power of the visible light is 5 to 15 W.

[0020] Preferably, the reaction temperature is 40-60° C.; the reaction time is 12-24 h.

[0021] Preferably, after the reaction is completed, vacuum concentration and silica gel column chromatography purification are also included.

[0022] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention develops a method for the efficient deoxidation reduction of tertiary amides to amines using low-valent tungsten catalysis with HBPin as a hydrogen source, using commercially available W(CO)6 as a catalyst, under visible light irradiation, without using other additives, the TON is as high as 2000, and the reaction has good functional group tolerance, and can be applied to the reduction of aromatic or aliphatic substituted tertiary amides. DETAILED DESCRIPTION

[0024] The present invention provides a method for the deoxygenation reduction of tertiary amides to amines promoted by visible light, comprising the following steps:

[0025]

[0026] In a protective gas atmosphere, a tertiary amide compound (1), pinacol borane, a tungsten catalyst and a solvent are mixed and reacted under the promotion of visible light to obtain an amine compound (2).

[0027] In the present invention, the R 1 Preferably, it is one of H, substituted or unsubstituted alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted aromatic heterocycle, substituted or unsubstituted furan, substituted or unsubstituted pyrrole, substituted or unsubstituted thiophene, and substituted or unsubstituted cycloalkyl;

[0028] The R 2 , R 3 Preferably, R 2, R 3 Form a ring.

[0029] In the present invention, the tungsten catalyst is preferably tungsten hexacarbonyl (W(CO)6).

[0030] In the present invention, the solvent is preferably one or more of n-hexane, ether, toluene, tetrahydrofuran, acetonitrile, dichloromethane, and 1,4-dioxane, more preferably one or more of n-hexane, tetrahydrofuran, and acetonitrile, and more preferably n-hexane.

[0031] In the present invention, the molar ratio of the tertiary amide compound, pinacol borane and tungsten catalyst is preferably 0.5-1:1.5-3:0.0005-0.05, more preferably 0.7-1:2-3:0.0005-0.01, and more preferably 1:3:0.0005.

[0032] In the present invention, the usage ratio of the tertiary amide compound and the solvent is preferably 0.5-1 mmol:1 mL, more preferably 0.7-1 mmol:1 mL, and more preferably 1 mmol:1 mL.

[0033] In the present invention, the wavelength of the visible light is preferably 405 nm; the light source power of the visible light is preferably 5 to 15 W, more preferably 8 to 12 W, and more preferably 10 W.

[0034] In the present invention, the reaction temperature is preferably 40-60°C, more preferably 45-55°C, and more preferably 50°C; the reaction time is preferably 12-24h, more preferably 14-16h, and more preferably 15h.

[0035] In the present invention, after the reaction is completed, vacuum concentration and silica gel column chromatography purification are also included.

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] The structure of 1a is: The structure of 2a is:

[0039] Preparation of 2a: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3008 g (1 mmol) of 1a, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added. The sealed tube was then placed in a UV reactor at 50°C (wavelength 405 nm, power 10 W). After stirring for 15 h, the mixture was concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.2639 g (0.92 mmol, yield 92%) of the product 2a. 1 H NMR (400MHz, CDCl3): δ7.39-7.37(m,6H),7.27-7.24(m,6H),7.18-7.14(m,3H),3.51(s,6H); 13 C NMR (100MHz, CDCl3): δ139.5,128.7,128.2,126.8,57.9.

[0040] Example 2

[0041] The structure of 1b is: The structure of 2b is:

[0042] Preparation of 2b: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3172 g (1 mmol) of 1b, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.2838 g (0.94 mmol, yield 94%) of the product 2b. 1 H NMR (400MHz, CDCl3): δ7.40(d,J=7.6Hz,4H),7.32-7.27(m,6H),7.23-7.20(m,2H),7.13-7.11(m,2H),3.54(s,4H),3.52(s,2H),2.32(s,3H); 13 C NMR (100MHz, CDCl3): δ139.7,136.4,136.2,128.9,128.7,128.2,126.8,57.8,57.6,21.1.

[0043] Example 3

[0044] The structure of 1c is: The structure of 2c is:

[0045] Preparation of 2c: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3310 g (1 mmol) of 1c, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.3047 g (0.96 mmol, yield 96%) of the product 2c. 1 H NMR (400MHz, CDCl3): δ7.39(d,J=7.6Hz,4H),7.32-7.29(m,6H),7.24-7.20(m,2H),6.85(d,J=8.4Hz,2H),3.79(s,3H),3.54(s,4H),3.49(s,2H); 13 C NMR (100MHz, CDCl3): δ158.5,139.7,131.4,129.8,128.6,128.1,126.8,113.5,57.7,57.1,55.1.

[0046] Example 4

[0047] The structure of 1d is: The structure of 2d is:

[0048] Preparation of 2d: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1707 g (0.5 mmol) of 1d, 218 μL (1.5 mmol) of HBpin, 100 μL (0.01 M, 0.001 mmol) of W(CO)6 in hexane and 900 μL of hexane were added, and then the sealed tube was placed in a 50°C UV reactor (wavelength 405 nm, power 10 W), stirred for 15 h, and concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.1548 g (0.47 mmol, yield 95%) of product 2d. IR (neat): 2921, 1614, 1522, 1347, 1068 cm -1 ; 1H NMR (400MHz, CDCl3): δ7.40-7.38(m,4H),7.30-7.23(m,6H),7.19-7.16(m,2H),6.70-6.67(m,2H),3.52(s,4H),3.46(s,2H),2.85(s,6H); 13 C NMR (100MHz, CDCl3): δ149.7,139.9,129.6,128.7,128.1,127.2,126.6,112.5,57.6,57.2,40.7.HRMS(ESI)[C 23 H 27 N2] + (M+H + ) was calculated to have a theoretical mass of m / z 331.2174, and the actual measured mass was m / z 331.2167.

[0049] Example 5

[0050] The structure of 1e is: The structure of 2e is:

[0051] Preparation of 2e: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1593 g (0.5 mmol) of 1e, 218 μL (1.5 mmol) of HBpin, 100 μL (0.025 M, 0.0025 mmol) of W(CO)6 in hexane and 900 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1513 g (0.495 mmol, yield 99%) of the product 2e. 1 HNMR (400MHz, CDCl3): δ7.38-7.27(m,10H),7.22-7.18(m,2H),7.00-6.95(m,2H),3.51(s,4H),3.48(s,2H); 13 C NMR (100MHz, CDCl3): δ161.9 (d, J = 243.0Hz), 139.4, 135.2 (d, J = 3.0Hz), 130.1 (d, J = 7.7Hz), 128.7, 128.2, 126.9, 115.1 (d, J = 21.0Hz), 57.8, 57.1; 19 F NMR (376 MHz, CDCl3): δ-116.0.

[0052] Example 6

[0053] The structure of 1f is: The structure of 2f is:

[0054] Preparation of 2f: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1694 g (0.5 mmol) 1f, 218 μL (1.5 mmol) HBpin, 250 μL (0.01 M, 0.0025 mmol) W(CO)6 hexane solution and 750 μL hexane were added, and then the sealed tube was placed in a 50°C UV reactor (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1672 g (0.5 mmol, yield 100%) of the product 2f. 1 H NMR (400MHz, CDCl3): δ7.37-7.35(m,4H),7.30-7.25(m,7H),7.23-7.18(m,3H),3.50(s,4H),3.46(s,2H); 13 C NMR (100MHz, CDCl3): δ139.3,138.1,132.4,130.0,128.7,128.3,128.2,126.9,57.8,57.1.

[0055] Example 7

[0056] The structure of 1g is: The structure of 2g is:

[0057] Preparation of 2g: In a glove box, under a nitrogen atmosphere, in a 15mL sealed tube equipped with a magnetic stirring bar, 0.3686g (1mmol) 1g, 435μL (3mmol) HBpin, 0.0181g (0.05mmol) W(CO)6 and 1mL hexane were added, and then the sealed tube was placed in a 50°C UV reactor (wavelength of 405nm, power of 10W), stirred for 15h, and concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.3667g (1.00mmol, yield 100%) of the product 2g. 1 H NMR (400MHz, CDCl3): δ7.54(d,J=8.0Hz,2H),7.49(d,J=8.4Hz,2H),7.39-7.37(m,4H),7.32-7.28(m,4H),7.23-7.19(m,2H),3.56-3.53(m,6H);13 C NMR (100MHz, CDCl3): δ144.0, 139.2, 128.8, 128.7, 128.3, 127.1, 125.1 (q, J = 4.0Hz), 124.3 (q, J = 271Hz), 58.1, 57.4; 19 F NMR (376 MHz, CDCl3): δ-62.3.

[0058] Example 8

[0059] The structure of 1h is: The structure of 2h is:

[0060] Preparation of 2h: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, add 0.1771 g (0.5 mmol) of 1h, 218 μL (1.5 mmol) of HBpin, and 1 mL (0.025 M, 0.025 mmol) of W(CO)6 in hexane solution, and then place the sealed tube in a 50°C UV reactor (wavelength of 405 nm, power of 10 W). After stirring for 15 h, concentrate in vacuo, and the residue is purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1695 g (0.49 mmol, yield 99%) of the product 2h. 1 H NMR (400MHz, CDCl3): δ7.99(d,J=8.4Hz,2H),7.48(d,J=8.0Hz,2H),7.39(d,J=6.8H z,4H),7.34-7.30(m,4H),7.25-7.21(m,2H),3.90(s,3H),3.59(s,2H),3.56(s,4H); 13 C NMR (100MHz, CDCl3): δ167.0,145.2,139.1,129.5,128.7,128.5,128.2,126.9,58.0,57.6,51.9.

[0061] Example 9

[0062] The structure of 1i is: The structure of 2i is:

[0063] Preparation of 2i: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3157 g (1 mmol) of 1i, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.2992 g (0.99 mmol, yield 99%) of the product 2i. 1 H NMR (400MHz, CDCl3): δ7.38(d,J=1.6Hz,4H),7.37-7.28(m,4H),7.24-7.15(m,5H),6.99(d,J=7.2Hz,1H),3.52-3.49(m,6H),2.30(s,3H); 13 CNMR (100MHz, CDCl3): δ139.6,139.5,137.6,129.4,128.7,128.2,128.1,127.6,126.8,125.8,57.9,21.4.

[0064] Example 10

[0065] The structure of 1j is: The structure of 2j is:

[0066] Preparation of 2j: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3283 g (1 mmol) of 1j, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.2884 g (0.92 mmol, yield 92%) of the product 2j. 1 H NMR (400MHz, CDCl3): δ7.40 (d, J = 7.6Hz, 4H), 7.33-7.29 (m, 3H), 7.24-7.20 (m, 4H) ,6.98(d,J=8.0Hz,2H),6.78-6.76(m,1H),3.81(s,3H),3.56(s,4H),3.53(s,2H); 13C NMR (100MHz, CDCl3): δ159.6,141.3,139.5,129.1,128.7,128.2,126.8,121.0,114.3,112.0,57.9,57.8,55.0.

[0067] Embodiment 11

[0068] The structure of 1k is: The structure of 2k is:

[0069] Preparation of 2k: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1549 g (0.5 mmol) of 1k, 218 μL (1.5 mmol) of HBpin, 100 μL (0.01 M, 0.001 mmol) of W(CO)6 in hexane and 900 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1338 g (0.44 mmol, yield 90%) of the product 2k. 1 HNMR (400MHz, CDCl3): δ7.47-7.45(m,1H),7.37-7.34(m,4H),7.29-7.27(m,4H),7.21-7.08(m,5H),3.51-3.50(m,6H),2.23(s,3H); 13 C NMR (100MHz, CDCl3): δ139.5,137.3,137.1,130.2,129.6,128.9,128.1,126.8,125.6,58.3,56.3,19.4.

[0070] Example 12

[0071] The structure of 1l is: The structure of 2l is:

[0072] Preparation of 2l: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3296 g (0.99 mmol) of 1l, 435 μL (3 mmol) of HBpin, 200 μL (0.01 M, 0.002 mmol) of W(CO)6 in hexane and 800 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.3020 g (0.95 mmol, yield 96%) of the product 2l. 1 H NMR (400MHz, CDCl3): δ7.61 (dd, J=7.6, 1.6Hz, 1H), 7.43-7.41 (m, 4H), 7.31-7.28 (m, 4H), 7.22 -7.17(m,3H),6.98-6.94(m,1H),6.83(d,J=8.4Hz,1H),3.78(s,3H),3.62(s,2H),3.59(s,4H); 13 C NMR (100MHz, CDCl3): δ157.7,140.0,129.6,128.6,128.1,127.7,127.5,126.7,120.4,110.1,58.2,55.1,51.2.

[0073] Example 13

[0074] The structure of 1m is: The structure of 2m is:

[0075] Preparation of 2m: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3456 g (1.01 mmol) of 1m, 435 μL (3 mmol) of HBpin, 400 μL (0.025 M, 0.01 mmol) of W(CO)6 in hexane and 600 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.2909 g (0.88 mmol, yield 88%) of the product 2m. 1HNMR (400MHz, CDCl3): δ7.39 (d, J = 7.6Hz, 4H), 7.33-7.29 (m, 4H), 7.24-7.20 (m, 2H), 6.95 ( s,1H),6.80(d,J=7.6Hz,1H),6.73(d,J=8.0Hz,1H),5.93(s,2H),3.53(s,4H),3.45(s,2H); 13 C NMR (100MHz, CDCl3): δ147.6,146.4,139.5,133.5,128.7,128.2,126.8,121.7,109.0,107.7,100.7,57.7,57.6.

[0076] Embodiment 14

[0077] The structure of 1n is: The structure of 2n is:

[0078] Preparation of 2n: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3247 g (0.99 mmol) of 1n, 435 μL (3 mmol) of HBpin, 200 μL (0.01 M, 0.002 mmol) of W(CO)6 in hexane and 800 μL of hexane were added, and then the sealed tube was placed in a 50°C UV reactor (wavelength 405 nm, power 10 W), stirred for 15 h, and concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.2769 g (0.89 mmol, yield 89%) of the product 2n. IR (neat): 2795, 1607, 1494, 1365, 1121 cm -1 ; 1 H NMR (400MHz, CDCl3): δ7.41-7.39(m,4H),7.33-7.29(m,4H),7.25-7.20(m,2H),7.00(s,2H),6.86(s,1H),3.54(s,4H),3.49(s,2H),2.31(s,6H); 13 C NMR (100MHz, CDCl3): δ139.7,139.4,137.5,128.7,128.5,128.2,126.8,126.6,57.93,57.92,21.3.HRMS(ESI)[C 23 H 26 N2] + (M+H +) was calculated to have a theoretical mass of m / z 316.2065, and the actual measured mass was m / z 316.2061.

[0079] Embodiment 15

[0080] The structure of 1o is: The structure of 2o is:

[0081] Preparation of 2o: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3514 g (1 mmol) of 1o, 435 μL (3 mmol) of HBpin, 50 μL (0.01 M, 0.0005 mmol) of W(CO)6 in hexane and 950 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.3197 g (0.95 mmol, yield 95%) of the product 2o. 1 H NMR (400MHz, CDCl3): δ7.82-7.79(m,4H),7.58(d,J=8.4Hz,1H),7.46-7.42(m,6H),7.34-7.30(m,4H),7.25-7.21(m,2H),3.71(s,2H),3.60(s,4H); 13 C NMR (100MHz, CDCl3): δ139.5,137.1,133.3,132.7,128.7,128.2,127.9,127.60,127.58,127.3,127.0,126.8,125.8,125.4,58.0,57.9.

[0082] Example 16

[0083] The structure of 1p is: The structure of 2p is:

[0084] Preparation of 2p: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1494 g (0.51 mmol) of 1p, 218 μL (1.5 mmol) of HBpin, and 1 mL (0.01 M, 0.01 mmol) of W(CO)6 in hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1383 g (0.5 mmol, yield 97%) of the product 2p. 1 H NMR (400MHz, CDCl3): δ7.41-7.36(m,5H),7.31-7.27(m,4H),7.22-7.18(m,2H),6.29(s,1H),6.16(d,J=3.2Hz,1H),3.60(s,2H),3.59(s,4H); 13 C NMR (100MHz, CDCl3): δ152.7,141.8,139.4,128.8,128.2,126.9,110.0,108.5,57.5,49.1.

[0085] Embodiment 17

[0086] The structure of 1q is: The structure of 2q is:

[0087] Preparation of 2q: In a glove box, in a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, add 0.1520 g (0.5 mmol) of 1q, 218 μL (1.5 mmol) of HBpin, and 1 mL (0.01 M, 0.01 mmol) of W (CO) 6 in hexane, then place the sealed tube in a 50°C UV reactor (wavelength 405 nm, power 10 W), stir for 15 h, and concentrate in vacuo. The residue is purified by silica gel column chromatography with PE / EtOAc (10 / 1) as the eluent to obtain 0.1330 g (0.46 mmol, yield 92%) of the product 2q. IR (neat): 3029, 1494, 1450, 1301, 1107 cm -1 ; 1 H NMR (400MHz, CDCl3): δ7.31-7.25(m,8H),7.21-7.18(m,2H),6.51-6.50(m 1H),6.05-6.04(m,1H),5.99-5.98(m,1H),3.49(s,4H),3.45-3.43(m,5H); 13C NMR (100MHz, CDCl3): δ139.5,129.4,129.1,128.1,126.8,122.5,109.9,106.2,58.0,50.0,33.9; HRMS(ESI)calculated for[C 20 H 23 N2] + (M+H + )requires m / z 291.1861, found m / z 291.1857.

[0088] Embodiment 18

[0089] The structure of 1r is: The structure of 2r is:

[0090] Preparation of 2r: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.3037 g (0.99 mmol) of 1r, 435 μL (3 mmol) of HBpin, 0.0177 g (0.05 mmol) of W(CO)6 and 1 mL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.2813 g (0.97 mmol, yield 97%) of the product 2r. 1 H NMR (400MHz, CDCl3): δ7.42-7.40(m,4H),7.30-7.28(m,4H),7.20-7.14(m,3H),6.88-6.85(m,2H),3.72(s,2H),3.57(s,4H); 13 CNMR (100MHz, CDCl3): δ143.2,139.2,128.6,128.2,126.9,126.3,125.4,124.6,57.5,52.1.

[0091] Embodiment 19

[0092] The structure of 1s is: The structure of 2s is:

[0093] Preparation of 2s: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1559 g (0.51 mmol) of 1s, 218 μL (1.5 mmol) of HBpin, 150 μL (0.01 M, 0.0015 mmol) of W(CO)6 in hexane and 850 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1357 g (0.46 mmol, yield 91%) of the product 2s. 1 HNMR (400MHz, CDCl3): δ7.35 (d, J = 7.2Hz, 4H), 7.29-7.26 (m, 4H), 7.21-7.17 (m 2H),3.49(s,4H),2.18(d,J=7.2Hz,2H),1.86-1.82(m,2H),1.66-1.58(m,4H),1.26-1.05(m,3H),0.78-0.68(m,2H); 13 C NMR (100MHz, CDCl3): δ140.1,128.7,128.0,126.6,60.8,58.8,35.7,31.6,26.8,26.2.

[0094] Embodiment 20

[0095] The structure of 1t is: The structure of 2t is:

[0096] Preparation of 2t: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1605 g (0.51 mmol) of 1t, 218 μL (1.5 mmol) of HBpin, 250 μL (0.01 M, 0.0025 mmol) of W(CO)6 in hexane and 750 μL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1227 g (0.412 mmol, yield 80%) of the product 2t. 1 HNMR (400MHz, CDCl3): δ7.32-7.15(m,13H),7.08-7.05(m,2H),3.63(s,4H),2.80-2.78(m,2H),2.72-2.70(m,2H); 13C NMR (100MHz, CDCl3): δ140.5,139.6,128.8,128.7,128.2,128.1,126.8,125.8,58.2,55.1,33.5.

[0097] Embodiment 21

[0098] The structure of 1u is: The structure of 2u is:

[0099] Preparation of 2u: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.2776 g (1 mmol) of 1u, 435 μL (3 mmol) of HBpin, 0.0181 g (0.05 mmol) of W(CO)6 and 1 mL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1089 g (0.41 mmol, yield 41%) of the product 2u. 1 H NMR (400MHz, CDCl3): δ7.37(d,J=7.6Hz,4H),7.32-7.29(m,4H),7.24-7.21(m,2H),3.59(s,4H),2.32(s,2H),0.79(s,9H); 13 C NMR (100MHz, CDCl3): δ140.2,129.1,128.0,126.7,65.8,60.8,33.0,28.4.

[0100] Embodiment 22

[0101] The structure of 1v is: The structure of 2v is:

[0102] Preparation of 2v: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.2270 g (1 mmol) 1v, 435 μL (3 mmol) HBpin, 50 μL (0.01 M, 0.0005 mmol) W(CO)6 hexane solution and 950 μL hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo. The residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.1772 g (0.81 mmol, yield 81%) of the product 2v. 1H NMR (400MHz, CDCl3): δ7.36-7.28(m,8H),7.24-7.16(m,2H),3.50(s,4H),2.17(s,3H); 13 C NMR (100MHz, CDCl3): δ139.3,128.9,128.2,126.9,61.8,42.2.

[0103] Embodiment 23

[0104] The structure of 1w is: The structure of 2w is:

[0105] Preparation of 2w: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.2617 g (1 mmol) 1w, 435 μL (3 mmol) HBpin, 50 μL (0.01 M, 0.0005 mmol) W(CO)6 hexane solution and 950 μL hexane were added, and then the sealed tube was placed in a 50°C UV reactor (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.2441 g (0.99 mmol, yield 99%) of the product 2w. 1 H NMR (400MHz, CDCl3): δ7.83-7.76(m,3H),7.67(s,1H),7.45-7.43(m,2H),7.39-7.36(m,1 H),7.23-7.21(m,2H),6.81(d,J=8.0Hz,2H),6.74-6.71(m,1H),4.68(s,2H),3.06(s,3H); 13 C NMR (100Hz, CDCl3): δ149.8,136.5,133.4,132.6,129.1,128.2,127.6,126.0,125.4,125.1,125.0,116.6,112.4,56.8,38.3.

[0106] Embodiment 24

[0107] The structure of 1x is: The structure of 2x is:

[0108] Preparation of 2x: In a glove box, under a nitrogen atmosphere, in a 15 mL sealed tube equipped with a magnetic stirring bar, 0.1894 g (0.99 mmol) of 1x, 435 μL (3 mmol) of HBpin, 0.0182 g (0.05 mmol) of W(CO)6 and 1 mL of hexane were added, and then the sealed tube was placed in a UV reactor at 50°C (wavelength of 405 nm, power of 10 W). After stirring for 15 h, the mixture was concentrated in vacuo, and the residue was purified by silica gel column chromatography with PE / EtOAc (10 / 1) as eluent to obtain 0.0915 g (0.52 mmol, yield 52%) of the product 2x. 1 H NMR (400MHz, CDCl3): δ7.33-7.23(m,5H),3.72(t,J=4.4Hz,4H),3.51(s,2H),2.46(t,J=4.4Hz,4H); 13 C NMR (100MHz, CDCl3): δ137.5,129.2,128.2,127.2,66.9,63.4,53.5.

[0109] Embodiment 25

[0110] Taking compounds 1a and 2a in Example 1 as an example, a Gram-scale reaction was carried out. See Example 1 for details, except that 1a was 1.0648 g (3.53 mmol), HBpin was 1523 μL (10.5 mmol), W(CO)6 was 175 μL (0.01 M, 0.00175 mmol) of a hexane solution of W(CO)6, hexane was 3.3 mL, the reaction time was 15 h, and 0.9141 g (3.2 mmol, 90% yield) of product 2a was obtained. 1 H NMR (400MHz, CDCl3): δ7.40-7.38(m,6H),7.30-7.27(m,6H),7.20-7.17(m,3H),3.53(s,6H).

[0111] Comparative Example 1

[0112] The preparation of compound 2a is specifically described in Example 1, except that no light irradiation was performed, the reaction temperature was 120° C., the yield of 2a was 28%, and the recovery rate of 1a was 71%.

[0113] Comparative Example 2

[0114] The preparation of compound 2a is specifically as described in Example 1, except that no light was irradiated, the reaction temperature was 120°C, and no catalyst W(CO)6 was contained. The yield of 2a was 29%, and the recovery rate of 1a was 71%.

[0115] According to the results of Comparative Examples 1 and 2, after deducting the background reaction, the tungsten catalyst does not catalyze the reaction at 120°C.

[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: The following steps are involved: In a protective gas atmosphere, a tertiary amide compound, pinacol borane, a tungsten catalyst and a solvent are mixed and reacted under the promotion of visible light to obtain an amine compound; The structure of the tertiary amide compound is: The structure of the amine compound is: Among them, the R 1 is one of H, substituted or unsubstituted alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted aromatic heterocycle, substituted or unsubstituted furan, substituted or unsubstituted pyrrole, substituted or unsubstituted thiophene, and substituted or unsubstituted cycloalkyl; The R 2 , R 3 R is independently one of an alkyl group, a benzene ring, a benzyl group, or 2 , R 3 Form a ring.

2. The method of claim 1 for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: The tungsten catalyst is tungsten hexacarbonyl.

3. The method of claim 2 for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: The solvent is one or more of n-hexane, ether, toluene, tetrahydrofuran, acetonitrile, dichloromethane and 1,4-dioxane.

4. The method for the visible light-promoted deoxygenation reduction of tertiary amides to amines according to claim 1 or 2, characterized in that: The molar ratio of the tertiary amide compound, pinacol borane and tungsten catalyst is 0.5-1:1.5-3:0.0005-0.

05.

5. The method of claim 4 for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: The usage ratio of the tertiary amide compound and the solvent is 0.5-1 mmol:1 mL.

6. The method of claim 5 for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: The wavelength of the visible light is 405nm; the light source power of the visible light is 5-15W.

7. A method for the visible light-promoted deoxygenation reduction of tertiary amides to amines according to claim 1 or 6, characterized in that: The reaction temperature is 40-60° C.; the reaction time is 12-24 hours.

8. The method of claim 7 for the visible light-promoted deoxygenation reduction of tertiary amides to amines, characterized in that: After the reaction is completed, vacuum concentration and silica gel column chromatography purification are also performed.

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