Method for electrochemical synthesis of gamma-aryl ester compounds

Abstract

The present invention provides a method for the electrochemical synthesis of γ-aryl ester compounds. Through an efficient electrochemical reduction strategy, a diazonium compound and an olefin undergo an addition reaction to produce γ-aryl ester compounds. This method operates under mild reaction conditions, does not require metal catalysts or chemical redox reagents, exhibits high functional group tolerance, and exhibits good synthetic practicality, showing potential for industrialization.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and in particular to a method for electrochemically synthesizing gamma-aryl ester compounds. Background Art

[0002] γ-Aryl ester compounds are chemical substances with diverse applications. As solvents, they are widely used in the coatings, inks, and adhesives industries, significantly improving the flow and adhesion properties of these products. In addition, γ-Aryl ester compounds can be added to various daily chemicals and foods as a fragrance ingredient to enhance the aroma of the products. Furthermore, these compounds are also important intermediates in drug synthesis. They can be converted into γ-aryl acids through hydrolysis, which have shown broad application prospects in the fields of anti-cancer treatment and digestive system disease drug development. Asymmetric reduction of ethyl 4-phenylbutyrate can also efficiently convert it into bioactive chiral compounds (ACS Catal. 2022, 12(9), 5136–5144).

[0003] Traditional methods for synthesizing 4-phenylbutyrate require the use of strong acids (such as concentrated sulfuric acid) to react with alkenes for a cis-addition reaction, which is a demanding process and produces byproducts. Currently, although the use of diazo compounds to generate alkyl radicals under the action of photocatalysis, which then add to alkenes, has become a new approach for synthesizing a series of γ-aryl esters, this strategy still faces challenges such as limited substrate applicability and high costs. For example, when using photoenzymatic strategies for the selective hydroalkylation of alkenes, diazo compounds are limited to 2-benzyldiazoacetate as a substrate (Angew. Chem. Int. Ed. 2022, 62, e202214135). Using Ru(bpy)3Cl2·6H2O as a photocatalyst, diazo compounds undergo a proton-coupled electron transfer (PCET) process to form alkyl radicals, which then add to alkenes, has also achieved the synthesis of γ-aryl esters. However, the catalyst is expensive and the reaction is difficult to scale up, limiting its promotion in practical applications. (J.Am.Chem.Soc.2020,142,32,13846–13855). Therefore, exploring a method for synthesizing γ-aryl ester compounds with mild reaction conditions, low production cost, and wide substrate applicability remains an important issue that needs to be addressed. Summary of the Invention

[0004] In order to solve the problems in the prior art, the present invention provides a method for electrochemically synthesizing γ-aryl ester compounds. The present invention uses a diazo compound and an olefin as reaction substrates to generate γ-aryl ester compounds.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A method for electrochemically synthesizing γ-aryl ester compounds, using compound 1 and compound 2 as raw materials, electrochemically synthesizes γ-ester derivative compound 3; the reaction formula is as follows:

[0007]

[0008] Among them, R 1 R is selected from alkyl, alkoxy, halogen or multiple halogen-substituted alkyl, aryl; 2 Selected from ester group and amide group.

[0009] According to one embodiment of the present invention, the alkyl group is selected from methyl and tert-butyl; the alkoxy group is selected from methoxy; the halogen is selected from fluorine, chlorine, and bromine; the multiple halogen-substituted alkyl groups are selected from trifluoromethyl; the aryl group is selected from phenyl, 2-naphthyl, 2-thienyl, 2-pyridyl, and 5-(4-methylthiazole); the ester group is selected from ethyl formate, tert-butyl formate, and 2-methoxyethyl formate; and the amide group is selected from N,N-diethylformamide.

[0010] According to one embodiment of the present invention, the compound 3 is selected from:

[0011]

[0012]

[0013] According to one embodiment of the present invention, the electrolytic cell used in the electrochemical synthesis method is an undivided electrolytic cell; the electrodes are one or more of stainless steel, Fe, Ni, Cu, Ag, Zn, foamed stainless steel, graphite sheet, graphite felt, carbon paper or reticulated glassy carbon; the electrolyte is one or more of tetra-n-butylammonium hexafluorophosphate, tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium acetate, tetra-n-butylammonium perchlorate and tetraethylammonium tetrafluoroborate; the current is 3 to 10 mA; and the reaction temperature is 0 to 50°C.

[0014] According to one embodiment of the present invention, the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetonitrile and methanol.

[0015] According to one embodiment of the present invention, the electrode foam stainless steel is the anode and the carbon paper is the cathode; the electrolyte is tetra-n-butylammonium acetate with an electrolyte concentration of 0.05M; the current is 5 mA; and the solvent is a mixed solution of N,N-dimethylacetamide and methanol (volume ratio of 3:1).

[0016] According to one embodiment of the present invention, the reaction temperature is 25°C.

[0017] According to one embodiment of the present invention, the molar ratio of the 4-phenylstyrene compound to the diazoacetic acid ester compound is 1:1-1:10; and the concentration of 4-phenylstyrene is 0.05M-0.2M.

[0018] According to one embodiment of the present invention, the molar ratio of the 4-phenylstyrene compound to the diazoacetic acid ester compound is 1:8; and the concentration of 4-phenylstyrene is 0.05M.

[0019] According to one embodiment of the present invention, the endpoint of the reaction is when thin layer chromatography shows that the starting material has completely disappeared.

[0020] According to one embodiment of the present invention, after the reaction is completed, water is added to quench the reaction, and the mixture is extracted three times with ethyl acetate. The organic phases are combined, and the organic phases are washed once with a saturated aqueous sodium chloride solution to obtain an organic phase. The solvent is concentrated under reduced pressure and purified by silica gel column chromatography using a mixture of ethyl acetate and petroleum ether as an eluent to obtain the product.

[0021] Beneficial effects:

[0022] This invention provides a method for the electrochemical synthesis of γ-aryl ester compounds. Through an efficient electrochemical reduction strategy, a diazo compound is reacted with an olefin to produce the γ-aryl ester compound. This method operates under mild reaction conditions, does not require metal catalysts or chemical redox reagents, exhibits high functional group tolerance, and exhibits good synthetic practicality, showing potential for industrialization. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Unless otherwise specified, the raw materials used in this application can be obtained commercially, and any range recorded in the present invention includes the end value and any numerical value between the end values ​​and any sub-range consisting of the end value or any numerical value between the end values.

[0024] The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

[0025] Example 1:

[0026] Preparation of ethyl 4-([1,1'-biphenyl]-4-yl)butanoate 3

[0027]

[0028] The specific procedure was as follows: 0.2 mmol of 4-phenylstyrene and 0.2 mmol of tetra-n-butylammonium acetate were placed in a 10 mL electrolytic cell equipped with a 1.0 cm × 1.2 cm × 0.1 cm stainless steel foam sheet as the anode and a 1.0 cm × 1.2 cm × 0.01 cm carbon paper sheet as the cathode. 3.0 mL of N,N-dimethylformamide and 1.0 mL of methanol were added as solvents. 144 μL of water and 1.6 mmol of ethyl diazoacetate were then added. The reaction was allowed to proceed at room temperature for 12 h at a current of 5 mA and monitored by TLC until the substrate was completely consumed. After completion of the reaction, the reaction was quenched with water and extracted three times with ethyl acetate. The organic phases were combined and washed once with saturated sodium chloride solution. The solvent was concentrated under reduced pressure and the product was purified by silica gel column chromatography using ethyl acetate and petroleum ether in a ratio of 1:80 as the eluent.

[0029] Table 1. Effect of different anode materials on the preparation of compound 3

[0030]

[0031] It can be seen from Table 1 that when the anode material is foamed stainless steel, the yield of the product can achieve relatively good results.

[0032] Table 2. Effect of different cathode materials on the preparation of compound 3

[0033]

[0034] It can be seen from Table 2 that when the cathode material is carbon paper, the yield of the product can achieve relatively good results.

[0035] Table 3. Effect of different currents (same charge Q = I·t) on the preparation of compound 3

[0036]

[0037] As shown in Table 3, when the current is 5 mA and the reaction time is 10 h, the yield of the product can achieve relatively good results.

[0038] Table 4. Effects of different solvents on the preparation of compound 3

[0039]

[0040] As can be seen from Table 4, when the solvent is a mixed solvent with a volume ratio of N,N-dimethylacetamide and methanol of 3:1, the yield of the product can achieve relatively good results.

[0041] Table 5. Effects of different electrolytes on the preparation of compound 3

[0042]

[0043] As shown in Table 5, when the electrolyte is tetra-n-butylammonium acetate, the yield of the product can achieve relatively good results.

[0044] Table 6. Effect of different electrolyte concentrations on the preparation of compound 3

[0045]

[0046] It can be seen from Table 6 that when the electrolyte concentration is 0.05 M, the yield of the product can achieve relatively good results.

[0047] Table 7. Effect of different temperatures on the preparation of compound 3

[0048]

[0049] As shown in Table 7, when the reaction temperature is room temperature (25° C.), the yield of the product can achieve relatively good results.

[0050] Investigation of substrate universality

[0051]

[0052] In summary, the present invention utilizes readily available and inexpensive aryl vinyl compounds and diazo compounds, using an efficient electrochemical reduction strategy to generate γ-aryl esters through an addition reaction between the diazo compound and olefin. This reaction requires no metal catalysts or chemical redox reagents, operates under mild reaction conditions, exhibits high functional group tolerance, and offers excellent synthetic practicality.

[0053] The specific structure and structural analysis data of compound 3-31 are as follows.

[0054] Compound 3: ethyl 4-([1,1'-biphenyl]-4-yl)butanoate, colorless oily liquid, isolated yield 71% (38 mg), 1 H NMR(600MHz,Chloroform-d)δ7.60(d,J=7.8Hz,2H),7.54(d,J=7.2Hz,2H),7.44(t,J=7.2Hz,2H),7.34(t,J=7.2Hz,1H),7.27( d,J=7.8Hz,2H),4.15(q,J=7.2Hz,2H),2.71(t,J=7.2Hz,2H),2.37(t,J=7.2Hz,2H),2.04-1.99(m,2H),1.28(t,J=6.6Hz,3H).

[0055] Compound 4: ethyl 4-(4'-methyl-[1,1'-biphenyl]-4-yl)butanoate, colorless oily liquid, isolated yield 59% (34 mg), 1 H NMR(600MHz,Chloroform-d)δ7.40(dd,J=14.4,7.8Hz,4H),7.14(dd,J=7.8,2.4Hz,4H),4.04(q,J=7.2Hz ,2H),2.59(t,J=7.2Hz,2H),2.29(s,3H),2.26(t,J=7.2Hz,2H),1.92-1.87(m,2H),1.16(t,J=7.2Hz,3H).

[0056] Compound 5: 4-(4'-chloro-[1,1'-biphenyl]-4-yl)butanoic acid ethyl ester. Colorless oily liquid, isolated yield 78% (47 mg), 1 H NMR(600MHz,Chloroform-d)δ7.39(dd,J=13.8,8.4Hz,4H),7.29(d,J=9.0Hz,2H),7.16(d,J=7.8Hz,2H),4. 02(q,J=7.2Hz,2H),2.57(t,J=7.8Hz,2H),2.23(t,J=7.2Hz,2H),1.90-1.85(m,2H),1.14(t,J=7.2Hz,3H).

[0057] Compound 6: 4-(3',5'-dimethyl-[1,1'-biphenyl]-4-yl)butanoic acid ethyl ester, colorless oily liquid, isolated yield of 82% (49 mg), 1 H NMR(600MHz,Chloroform-d)δ7.43(d,J=7.8Hz,2H),7.16(d,J=8.4Hz,2H),7.12(s,2H),6.90(s,1H),4.06(q,J= 7.2Hz,2H),2.62(t,J=7.8Hz,2H),2.30(s,6H),2.28(t,J=7.2Hz,2H),1.94-1.89(m,2H),1.19(t,J=7.2Hz,3H).

[0058] Compound 7: ethyl 4-(3',5'-bis(trifluoromethyl)-[1,1'-biphenyl]-4-yl)butanoate, colorless oily liquid, isolated yield 86% (70 mg), 1H NMR(600MHz,Chloroform-d)δ8.00(s,2H),7.84(s,1H),7.54(d,J=7.8Hz,2H),7.33(d,J=7.8Hz,2H), 4.15(q,J=6.6Hz,2H),2.73(t,J=7.8Hz,2H),2.36(t,J=7.2Hz,2H),2.0(m,2H),1.27(t,J=7.2Hz,3H).

[0059] Compound 8: ethyl 4-(4-(naphthalen-2-yl)phenyl)butanoate, colorless oily liquid, isolated yield 86% (55 mg), 1 H NMR(600MHz,Chloroform-d)δ8.07(s,1H),7.93(t,J=6.6Hz,2H),7.89(d,J=7.8Hz,1H),7.78(dd,J=8.4,1.8Hz,1H),7.69(d,J=8.4Hz,2H),7.56- 7.48(m,2H),7.34(d,J=7.8Hz,2H),4.19(q,J=7.2Hz,2H),2.76(t,J=7.8 Hz,2H),2.41(t,J=7.2Hz,2H),2.08-2.03(m,2H),1.31(t,J=7.2Hz,3H). 13 C NMR (150MHz, CDCl3) δ172.41,139.62,137.73,137.28,132.64,131.46,127.96,127.30,12 7.08,126.56,126.31,125.17,124.74,124.44,124.43,59.23,33.73,32.63,25.48,13.22.

[0060] Compound 9: ethyl 4-phenylbutyrate, colorless oily liquid, isolated yield 58% (67 mg). 1 HNMR(600MHz,Chloroform-d)δ7.29(t,J=7.2Hz,2H),7.20(t,J=7.8Hz,3H),4.13(q,J=6.6Hz ,2H),2.66(t,J=7.2Hz,2H),2.33(t,J=7.2Hz,2H),1.99-1.94(m,2H),1.26(t,J=6.6Hz,3H).

[0061] Compound 10: ethyl 4-(p-tolyl)butanoate, colorless oily liquid, isolated yield 30% (37 mg). 1HNMR(600MHz,Chloroform-d)δ7.10(d,J=7.8Hz,2H),7.07(d,J=7.8Hz,2H),4.13(q,J=6.6 Hz,2H),2.62(t,J=7.2Hz,2H),2.34-2.31(m,5H),1.96-1.91(m,2H),1.26(t,J=7.2Hz,3H).

[0062] Compound 11: ethyl 4-(4-(tert-butyl)phenyl)butanoate, colorless oily liquid, isolated yield 50% (75 mg). 1 H NMR(600MHz,Chloroform-d)δ7.32(d,J=8.4Hz,2H),7.13(d,J=8.4Hz,2H),4.13(q,J=7.2Hz,2H),2 .63(t,J=7.8Hz,2H),2.34(t,J=7.2Hz,2H),1.99-1.94(m,2H),1.32(s,9H),1.26(t,J=7.2Hz,3H).

[0063] Compound 12: ethyl 4-(4-fluorophenyl)butanoate, colorless oily liquid, isolated yield 30% (38 mg). 1 HNMR (600MHz, Chloroform-d) δ7.13 (dd, J=8.4, 5.4Hz, 2H), 6.96 (t, J=8.4Hz, 2H), 4.12 (q, J=7. 2Hz,2H),2.62(t,J=7.2Hz,2H),2.30(t,J=7.2Hz,2H),1.95-1.90(m,2H),1.25(t,J=7.2Hz,3H).

[0064] Compound 13: ethyl 4-(4-chlorophenyl)butyrate, colorless oily liquid, isolated yield 52% (71 mg). 1 HNMR(600MHz,Chloroform-d)δ7.26-7.23(m,2H),7.10(d,J=8.4Hz,2H),4.12(q,J=7.2Hz, 2H),2.62(t,J=7.8Hz,2H),2.30(t,J=7.2Hz,2H),1.95-1.90(m,2H),1.25(t,J=7.2Hz,3H).

[0065] Compound 14: ethyl 4-(4-bromophenyl)butyrate, colorless oily liquid, isolated yield 50% (81 mg). 1HNMR(600MHz,Chloroform-d)δ7.41-7.38(dt,J=9.0,2.4Hz,2H),7.06-7.04(dt,J=9.0,2.4Hz,2H),4.12 (q,J=7.2Hz,2H),2.60(t,J=7.8Hz,2H),2.30(t,J=7.2Hz,2H),1.95-1.90(m,2H),1.25(t,J=7.2Hz,3H).

[0066] Compound 15: ethyl 4-(4-(trifluoromethyl)phenyl)butanoate, colorless oily liquid, isolated yield 63% (98 mg). 1 H NMR(600MHz,Chloroform-d)δ7.54(d,J=8.4Hz,2H),7.29(d,J=8.4Hz,2H),4.13(q,J=7.2Hz ,2H),2.71(t,J=7.2Hz,2H),2.32(t,J=7.2Hz,2H),1.99-1.94(m,2H),1.25(t,J=7.2Hz,3H).

[0067] Compound 16: ethyl 4-(2-methoxyphenyl)butanoate, colorless oily liquid, isolated yield 40% (36 mg). 1 HNMR(600MHz,Chloroform-d)δ7.18(td,J=7.8,1.8Hz,1H),7.12(dd,J=7.2,1.8Hz,1H),6.88(td,J=7.8,1.2Hz,1H),6.84(d,J=8. 4Hz, 1H), 4.12 (q, J = 7.2Hz, 2H), 3.81 (s, 3H), 2.66 (t, J = 7.2, 2H), 2.32 (t, J = 7.8Hz, 2H), 1.95-1.90 (m, 2H), 1.25 (t, J = 6.6Hz, 3H).

[0068] Compound 17: ethyl 4-(2-chlorophenyl)butanoate, colorless oily liquid, isolated yield 60% (82 mg). 1HNMR(600MHz,Chloroform-d)δ7.33(dd,J=7.8,1.2Hz,1H),7.21(dd,J=7.8,1.8Hz,1H),7.18(td,J=7.2,1.2Hz,1H),7.14(td,J =7.2,1.8Hz,1H),4.13(q,J=7.2Hz,2H),2.78(t,J=7.8Hz,2H),2.35(t,J=7.2Hz,2H),1.99-1.94(m,2H),1.26(t,J=7.2Hz,3H).

[0069] Compound 18: ethyl 4-(2-bromophenyl)butyrate, colorless oily liquid, isolated yield 70% (114 mg). 1 HNMR(600MHz,Chloroform-d)δ7.52(d,J=8.4Hz,1H),7.25-7.20(m,2H),7.06(ddd,J=7.8,6.6,2.4Hz,1H),4 .13(q,J=7.2Hz,2H),2.78(t,J=7.8Hz,2H),2.36(t,J=7.2Hz,2H),1.99-1.94(m,2H),1.26(t,J=7.2Hz,3H).

[0070] Compound 19: ethyl 4-(3-fluorophenyl)butanoate, colorless oily liquid, isolated yield 62% (78 mg). 1 HNMR(600MHz,Chloroform-d)δ7.25-7.21(m,1H),6.95(d,J=7.8Hz,1H),6.90–6.86(m,1H),4.13(q, J=6.6Hz,2H),2.65(t,J=7.2Hz,2H),2.31(t,J=7.2Hz,2H),1.97-1.92(m,2H),1.25(t,J=7.2Hz,3H).

[0071] Compound 20: ethyl 4-(3-chlorophenyl)butanoate, colorless oily liquid, isolated yield 57% (78 mg). 1 HNMR(600MHz,Chloroform-d)δ7.22-7.14(m,3H),7.05(d,J=7.2Hz,1H),4.12(q,J=7.2Hz, 2H), 2.63 (t, J=7.8Hz, 2H), 2.31 (t, J=7.2Hz, 2H), 1.96-1.91 (m, 2H), 1.25 (t, J=7.2Hz, 3H).

[0072] Compound 21: ethyl 4-(3-bromophenyl)butyrate, colorless oily liquid, isolated yield 56% (91 mg). 1 HNMR(600MHz,Chloroform-d)δ7.34-7.31(m,2H),7.15(t,J=7.8Hz,1H),7.10(dt,J=7.2,1.2Hz,1H),4.1 3(q,J=7.2Hz,2H),2.62(t,J=7.2Hz,2H),2.31(t,J=7.2Hz,2H),1.96-1.91(m,2H),1.26(t,J=7.2Hz,3H).

[0073] Compound 22: ethyl 4-(2-naphthyl)butanoate, colorless oily liquid, isolated yield 50% (73 mg). 1 H NMR(600MHz,Chloroform-d)δ7.83(d,J=7.8Hz,1H),7.80(d,J=8.4Hz,2H),7.64(s,1H),7.51-7.43(m,2H),7.36(dd,J=8.4 ,1.2Hz,1H),4.16(q,J=7.2Hz,2H),2.85(t,J=7.2Hz,2H),2.38(t,J=7.2Hz,2H),2.11-2.06(m,2H),1.28(t,J=7.2Hz,3H).

[0074] Compound 23: ethyl 4,4-diphenylbutyrate, colorless oily liquid, isolated yield 67% (72 mg). 1 H NMR(600MHz,Chloroform-d)δ7.28-7.19(m,8H),7.14(t,J=7.2Hz,2H),4.06(q,J=6.6Hz,2H ),3.89(t,J=7.8Hz,1H),2.35(q,J=7.8Hz,2H),2.23(t,J=7.2Hz,2H),1.19(t,J=7.2Hz,3H).

[0075] Compound 24: 4-phenylpentanoic acid ethyl ester, colorless oily liquid, isolated yield 37% (31 mg). 1 HNMR(600MHz,Chloroform-d)δ7.31-7.27(m,2H),7.21-7.16(m,3H),4.08(qd,J=7.2,2.4Hz,2H),2. 76-2.66(m,1H),2.24-2.13(m,2H),1.99-1.84(m,2H),1.27(d,J=7.2Hz,3H),1.22(t,J=7.2Hz,3H).

[0076] Compound 25: (R)-3,4-diphenylbutyric acid ethyl ester, colorless oily liquid, isolated yield 22% (24 mg). 1 HNMR(600MHz,Chloroform-d)δ7.28-7.12(m,8H),7.05(d,J=7.2Hz,2H),3.98(qd,J=7.2,1 .8Hz,2H),3.44-3.39(m,1H),2.95-2.88(m,2H),2.71-2.54(m,2H),1.10(t,J=7.2Hz,3H).

[0077] Compound 26: ethyl 4-(thiophen-2-yl)butanoate, colorless oily liquid, isolated yield 20% (16 mg). 1 HNMR(600MHz,Chloroform-d)δ7.12(dd,J=4.8,1.2Hz,1H),6.92(dd,J=4.8,2.4Hz,1H),6.80(dd,J=2.4,1.2Hz,1 H), 4.13 (q, J = 6.6Hz, 2H), 2.88 (t, J = 7.2Hz, 2H), 2.36 (t, J = 7.2Hz, 2H), 2.03-1.98 (m, 2H), 1.26 (t, J = 7.2Hz, 3H).

[0078] Compound 27: methyl 4-(4-methylthiazol-5-yl)butanoate, colorless oily liquid, isolated in 45% yield (36 mg). 1 HNMR(600MHz,Chloroform-d)δ8.55(s,1H),3.67(s,3H),2.80(t,J=7.2Hz,2H),2.37(s,3H),2.35(t,J=7.2Hz,2H),1.96-1.92(m,2H).The spectral data were inaccordance with those reported in the literature.

[0079] Compound 28: ethyl 4-(pyridin-2-yl)butanoate, colorless oily liquid, isolated yield 40% (31 mg). 1HNMR(600MHz,Chloroform-d)δ8.58-8.44(m,1H),7.60(td,J=7.2,1.8Hz,1H),7.16(d,J=7.8Hz,1H),7.11(dd,J=7.2,5 .4Hz,1H),4.12(q,J=6.6Hz,2H),2.83(t,J=7.2Hz,2H),2.36(t,J=7.2Hz,2H),2.10-2.05(m,2H),1.25(t,J=7.2Hz,2H).

[0080] Compound 29: tert-Butyl 4-([1,1'-biphenyl]-4-yl)butanoate, colorless oily liquid, isolated yield 63% (37 mg). 1 H NMR(600MHz,Chloroform-d)δ7.62-7.58(m,2H),7.56-7.52(m,2H),7.47-7.41(m,2H),7.37-7.31(m,1 H),7.28(d,J=8.4Hz,2H),2.70(t,J=7.2Hz,2H),2.29(t,J=7.2Hz,2H),2.00-1.95(m,2H),1.48(s,9H). 13 C NMR (150MHz, CDCl3) δ171.85,140.02,139.73,137.85,127.89,127.67,126.06,125.98,125.95,79.12,33.93,33.74,27.11,25.70.

[0081] Compound 30: 2-methoxyethyl 4-([1,1'-biphenyl]-4-yl)butanoate, colorless oily liquid, isolated in 54% yield (32 mg). 1 HNMR(600MHz,Chloroform-d)δ7.50(dd,J=7.8,1.8Hz,2H),7.44(d,J=8.4Hz,2H),7.35(t,J=7.2Hz,2H),7.25(t,J=7.2Hz,1H),7.17(d, J=7.8Hz,2H),4.16(t,J=4.8Hz,2H),3.51(t,J=4.8Hz,2H),3.31(s,3H),2.62(t,J=7.2Hz,2H),2.33(t,J=7.2Hz,2H),1.95-1.90(m,2H).

[0082] Compound 31: 4-([1,1'-biphenyl]-4-yl)-N,N-diethylbutanamide, colorless oily liquid, isolated in 27% yield (16 mg).1 HNMR(600MHz,Chloroform-d)δ7.43(dd,J=7.2,1.2Hz,2H),7.37(d,J=7.8Hz,2H),7.28(t,J=7.2Hz,2H),7.20-7.15(m,1H),7.14-7.10(m,2H),3.23(q,J=6.6Hz,2H),3.10(q,J=7.2Hz,2H),2.58(t,J=7.2Hz,2H),2.19(t,J=7.2Hz,2H),1.94-1.82(m,2H),1.01-0.88(m,6H)。

Claims

1. A method for electrochemically synthesizing γ-aryl ester compounds, using compound 1 and compound 2 as raw materials to electrochemically synthesize a γ-ester derivative compound 3; the reaction formula is as follows: in, R 1 R is selected from alkyl, alkoxy, halogen or multiple halogen-substituted alkyl, aryl; 2 The electrochemical synthesis method comprises the following steps: the electrolytic cell used in the electrochemical synthesis method is an undivided electrolytic cell, wherein the anode is foamed stainless steel or niobium sheet, and the cathode is carbon paper; the electrolyte is one or more of tetra-n-butylammonium hexafluorophosphate, tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium acetate, tetra-n-butylammonium perchlorate, and tetraethylammonium tetrafluoroborate; the current is 3 to 10 mA; the reaction temperature is 0 to 50° C.; and the solvent is a mixed solution of N,N-dimethylacetamide and methanol in a volume ratio of 3:

1.

2. The method according to claim 1, wherein: The alkyl group is selected from methyl and tert-butyl; the alkoxy group is selected from methoxy; the halogen is selected from fluorine, chlorine, and bromine; the alkyl group substituted with multiple halogens is selected from trifluoromethyl; the aryl group is selected from phenyl, 2-naphthyl, 2-thienyl, 2-pyridyl, and 5-(4-methylthiazole); the ester group is selected from ethyl formate, tert-butyl formate, and 2-methoxyethyl formate; and the amide group is selected from N,N-diethylformamide.

3. The method according to claim 1, wherein: The compound 3 is selected from:

4. The method according to claim 1, wherein: In the electrode, the foam stainless steel is the anode and the carbon paper is the cathode; the electrolyte is tetra-n-butylammonium acetate with an electrolyte concentration of 0.05M; and the current is 5 mA.

5. The method according to claim 4, wherein The reaction temperature was 25°C.

6. The method according to claim 5, wherein The molar ratio of the 4-phenylstyrene compound to the diazoacetic acid ester compound is 1:1-1:10; and the concentration of the 4-phenylstyrene is 0.05M-0.2M.

7. The method according to claim 6, wherein The molar ratio of the 4-phenylstyrene compound to the diazoacetic acid ester compound is 1:8; the concentration of 4-phenylstyrene is 0.05M.

8. The method according to claim 7, wherein After the reaction is completed, water is added to quench the reaction, and the mixture is extracted three times with ethyl acetate. The organic phases are combined and washed once with a saturated aqueous sodium chloride solution to obtain an organic phase. The solvent is concentrated under reduced pressure and the mixture is purified by silica gel column chromatography using a mixture of ethyl acetate and petroleum ether as an eluent to obtain the product.

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