A method for preparing indane compounds under electrochemical conditions

Abstract

The application belongs to the field of electrochemical synthesis, and discloses a method for preparing indane compounds under electrochemical conditions. The method uses inexpensive nickel as a catalyst to realize the cycloaddition reaction of 1,6-diynyl and alkyne under electrolytic conditions at room temperature, and rapidly and efficiently synthesizes indane compounds. The method can be applied to the cycloaddition reaction of 1,6-diynyl derived from the barbituric acid, a sedative and hypnotic, and 2,6-dichloro-5-fluoronicotinic acid ethyl ester, a medical intermediate, and synthesizes indane compounds containing a pharmacologically active fragment. The method has green and mild reaction conditions, does not need heating and uses a noble metal catalyst, has low reaction cost, and has good application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electrochemical synthesis, and particularly relates to a method for preparing indane compounds under electrochemical conditions, in particular, synthesizing indane compounds from 1,6-diynes and alkynes through a cycloaddition reaction under the synergistic effect of electrochemistry and nickel catalysis. BACKGROUND

[0002] The indane skeleton, as an important mother nucleus structure, widely exists in natural product molecules and drug molecules, such as the antiviral drug indinavir, the insomnia treatment drug ramelteon, the Parkinson's disease treatment drug rasagiline, and the natural products Caraphenol B, Fredercamycin A, (+)-Mutisianthol and Pallidol. In addition, it can also be used as an advantage fragment for the design of chiral ligands and catalysts, such as chiral carbene-indane catalysts, SPINOL chiral phosphine ligands, and chiral bisoxazoline ligands, etc. Therefore, synthesizing indane compounds with structural diversity has important application value.

[0003] At present, the common synthesis methods of indane compounds include intramolecular Friedel-Crafts alkylation, metal-catalyzed intramolecular Heck coupling, intramolecular radical cyclization and intramolecular Michael addition (Chem. Eur. J., 2016, 22, 5056-5094). Compared with various intramolecular cyclization reactions, the [2+2+2] cycloaddition reaction between 1,6-diynes and alkynes not only has easy-to-obtain raw materials, but also facilitates the rapid construction of more complex indane compounds. For example, at a high temperature of 110℃, rhodium trichloride can catalyze 1,6-diynes and alkynes to rapidly and efficiently synthesize indane compounds (Adv. Synth. Catal., 2015, 357, 1387-1392); under the synergistic effect of photo-oxidation-reduction cycle and metal catalysis (Mn, Co), 1,6-diynes and monoyne can efficiently synthesize a series of indane compounds, but the reaction system also needs to use the noble metal iridium as a photosensitizer, and the reaction cost is high (J. Am. Chem. Soc., 2016, 138, 15527-15530; Adv. Synth. Catal., 2024, 366, 1545-1550). SUMMARY

[0004] In order to overcome the shortcomings and deficiencies existing in the prior art, the purpose of the present application is to provide a method for preparing indane compounds under electrochemical conditions; the method uses inexpensive nickel as a catalyst to achieve the rapid and efficient synthesis of indane compounds from 1,6-diynes and alkynes under electrolytic conditions at room temperature; the method has green and mild reaction conditions, does not require heating or the use of noble metal catalysts, has low reaction cost, and has good application value.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A method for preparing indane compounds under electrochemical conditions, comprising the following operation steps: using 1,6-diynes and monoyne as raw materials, synthesizing indane compounds under the action of a nickel catalyst and a ligand; the 1,6-diyne has the structure shown in the following formula I, and the substituents R 1 and R 2 are one of ester groups, amide groups, acyl groups and cyano groups; the monoyne has the structure shown in the following formula II, and the substituents R 3 and R 4 are one of C1-C6 linear and cyclic alkyl groups, aryl groups and aromatic heterocyclic groups; the ligand is a compound having the structure shown in the following formula L or L', and the substituents R 5 and R 6 are one of C1-C6 linear and cyclic alkyl groups and aryl groups; the indane compound has the structure shown in the following formula III:

[0007]

[0008] The above-mentioned method for preparing indane compounds under electrochemical conditions specifically comprises the following operation steps: dissolving 1,6-diyne, monoyne, nickel catalyst, ligand, additive and electrolyte in an organic solvent, stirring until all the solids are dissolved, assembling the obtained electrolyte solution into an electrolytic cell, performing constant current electrolysis under room temperature conditions, the current intensity is 10 mA / mmol based on the amount of substance of 1,6-diyne, and after electrolysis is completed, the indane compound is obtained through post-treatment.

[0009] The molar ratio of the 1,6-diyne, monoyne, nickel catalyst, ligand, additive and electrolyte is 1:(1-3):(0.1-0.3):(0.1-0.5):(0.1-1):(0.5-2).

[0010] The post-treatment is to ultrasonically clean the electrodes with ethyl acetate twice after electrolysis is completed, combine the ethyl acetate cleaning liquids, and combine them with the electrolyte solution in the electrolytic cell, then wash them with deionized water twice, dry the obtained organic phase with anhydrous sodium sulfate, concentrate under reduced pressure, and separate the indane compound by column chromatography.

[0011] The nickel catalyst is one or any of bromide nickel, chloride nickel, chloride nickel dimethoxyethane (NiCl2·DME), nickel acetate, nickel perchlorate, nickel acetylacetone, and nickel nitrate.

[0012] The organic solvent is one or any of acetonitrile, acetone, ethyl acetate, N,N-dimethyl sulfoxide, N,N-dimethyl formamide, and N,N-dimethyl acetamide (DMA), and preferably, the organic solvent is N,N-dimethyl acetamide.

[0013] The electrolyte is one or any of quaternary ammonium perchlorate, quaternary ammonium tetrafluoroborate, quaternary ammonium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate; and the additive is one or any of triethylamine, triethanolamine, and diisopropyl ethylamine (DIPEA).

[0014] The anode material used in the electrolytic cell is one or any of platinum, graphite, carbon fiber, carbon felt, carbon paper, glassy carbon, and foamed glassy carbon; and the cathode material used in the electrolytic cell is one or any of foamed nickel, foamed copper, carbon fiber, carbon felt, carbon paper, glassy carbon, and foamed glassy carbon.

[0015] The anode material is carbon fiber, and the cathode material is foamed glassy carbon.

[0016] The room temperature is 25℃.

[0017] The reaction equation of the method for preparing the indane compound under the above electrochemical conditions is as follows:

[0018]

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] (1) The present application uses inexpensive metal nickel as a catalyst, without using noble metals such as rhodium and iridium, and has low reaction cost.

[0021] (2) The raw materials used in the present application are widely available and easy to synthesize and prepare on a large scale, and the synthesized indane compound structure is more diverse.

[0022] (3) The electrolysis process of the present application replaces the use of reducing agents such as zinc powder and manganese powder, and the reaction is carried out at room temperature, and the reaction system is simple, green, and mild.

[0023] (4) The method of the present application can be applied to the cycloaddition reaction of the sedative and hypnotic barbituric acid and the medical intermediate 2,6-dichloro-5-fluoro nicotinic acid ethyl ester derived 1,6-diyne, and an indane compound containing a pharmacologically active fragment is synthesized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 NMR spectrum of hydrogen spectrum of structural formula III-1 in Example 1.

[0025] Figure 2 NMR spectrum of carbon spectrum of structural formula III-1 in Example 1.

[0026] Figure 3 NMR spectrum of hydrogen spectrum of structural formula III-2 in Example 2.

[0027] Figure 4 NMR spectrum of carbon spectrum of structural formula III-2 in Example 2.

[0028] Figure 5 NMR spectrum of hydrogen spectrum of structural formula III-3 in Example 3.

[0029] Figure 6 NMR spectrum of carbon spectrum of structural formula III-3 in Example 3.

[0030] Figure 7 NMR spectrum of hydrogen spectrum of structural formula III-4 in Example 4.

[0031] Figure 8 NMR spectrum of carbon spectrum of structural formula III-4 in Example 4.

[0032] Figure 9 NMR spectrum of fluorine spectrum of structural formula III-4 in Example 4. DETAILED DESCRIPTION

[0033] The present application will be further described in conjunction with the examples and the accompanying drawings, but the embodiments of the present application are not limited thereto. The equipment and reagents used in the present application are commonly used in the art. It should be understood that the examples described herein are merely used to explain the present application, and are not intended to limit the present application.

[0034] The reaction equation of the method of the present application is as follows:

[0035]

[0036] The synthesis method of the indane compound with the structure as shown in formula III is as follows:

[0037] In a one-chamber electrolysis cell, 1,6-diyns represented by structural formula I, monoacetylenes represented by structural formula II, additives, Ni catalyst, ligands represented by structural formula L or L', electrolyte, in a molar ratio of 1:(1-3):(0.1-0.3):(0.1-0.5):(0.1-1):(0.5-2) are added together into a DMA solvent, and stirred thoroughly until all solids are dissolved. The obtained electrolyte solution is assembled into an electrolysis cell together with an anode and a cathode, and the system is sealed. Nitrogen gas is bubbled into the electrolyte solution for 15 minutes, and constant current electrolysis is carried out at room temperature. After electrolysis, the electrodes are cleaned with ethyl acetate by ultrasonic cleaning for two times, the ethyl acetate cleaning solution is combined, and then washed with deionized water for two times. The organic phase is dried with anhydrous sodium sulfate, concentrated under reduced pressure, and column chromatography is used to separate to obtain indane compounds represented by structural formula III.

[0038] The nickel catalyst is one or any combination of nickel bromide, nickel chloride, nickel chloride dimethoxyethane (NiCl2·DME), nickel acetate, nickel perchlorate, nickel acetylacetone, and nickel nitrate. The organic solvent is one or any combination of acetonitrile, acetone, ethyl acetate, N,N-dimethyl sulfoxide, N,N-dimethyl formamide, and N,N-dimethyl acetamide (DMA). The electrolyte is one or any combination of quaternary ammonium perchlorate, quaternary ammonium tetrafluoroborate, quaternary ammonium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate; the additive is one or any combination of triethylamine, triethanolamine, and diisopropyl ethylamine (DIPEA). The material of the anode is one or any combination of platinum, graphite, carbon fiber, carbon felt, carbon paper, glassy carbon, and foamed glassy carbon; the material of the cathode is one or any combination of foamed nickel, foamed copper, carbon fiber, carbon felt, carbon paper, glassy carbon, and foamed glassy carbon.

[0039] The application is further described below by specific examples in conjunction with the accompanying drawings:

[0040] Example 1

[0041] The equation of the synthesis method of this example is as follows:

[0042]

[0043] In a one-compartment electrolysis cell, 1,6-diynene of structural formula I-1 (0.2 mmol, 47 mg), monoynene of structural formula II-1 (0.4 mmol, 51 mg), DIPEA (0.24 mmol, 31 mg), NiCl2·DME (0.03 mmol, 6.6 mg), monodentate phosphine ligand of structural formula L1 tri-n-butylphosphine (0.06 mmol, 15 μL), nBu4NBF4(0.3 mmol, 99 mg) were added into 3 mL of DMA solvent, and the mixture was stirred until the solid was completely dissolved. The resulting electrolyte solution was assembled into an electrolysis cell together with a carbon fiber anode (0.15 g) and a foamed glassy carbon cathode (0.5 x 2.5 x 0.2 mm 3 ), and the system was sealed. Nitrogen gas was bubbled into the electrolyte solution for 15 minutes, and then the electrolysis was carried out at room temperature under a constant current of 2 mA for 8 hours. After the electrolysis was completed, the electrodes were washed with 10 mL of ethyl acetate twice, and the ethyl acetate washing solution was combined with the electrolyte solution in the electrolysis cell, and then washed with 30 mL of deionized water twice. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by column chromatography to obtain 57 mg of colorless oil, with a yield of 78%. The proton nuclear magnetic resonance spectrum of the product is shown in Figure 1 , the carbon nuclear magnetic resonance spectrum is shown in Figure 2 , and the nuclear magnetic resonance and mass spectrometry characterization data of the product are as follows: 1 H NMR (500 MHz, Chloroform-d) δ 7.72-7.68 (m, 2H), 7.66-7.62 (m, 2H), 7.43-7.38 (m, 2H), 7.30 (d, J = 7.8 Hz, 1H), 3.77 (s, 6H), 3.65 (d, J = 5.7 Hz, 4H). 13 C NMR (126 MHz, Chloroform-d) δ 172.06, 145.84, 141.18, 140.81, 138.44, 132.70, 127.81, 126.45, 125.02, 123.25, 119.15, 110.81, 60.52, 53.25, 40.60, 40.44. HRMS (EI): exact mass calculated for C 20 H 17 NO4[M]+require m / z = 335.1158, found m / z = 335.1161. The characterization data prove that the obtained product is an indane compound with the structure shown in formula III-1.

[0044] Comparative Example 1

[0045]

[0046] Other steps are the same as in Example 1, except that no ligand is added or the ligand used is different, using the ligand of the structure shown in Formula L2, L1' or L2' instead of tri-n-butylphosphine of the structure shown in Formula L1, respectively. The reaction results are as follows: the yield of the product obtained in the comparative experiment using the compound of the structure shown in Formula L2 as the ligand is 71%; the yield of the product obtained in the comparative experiment using the compound of the structure shown in Formula L1' as the ligand is 35%; the yield of the product obtained in the comparative experiment using the compound of the structure shown in Formula L2' as the ligand is 76%; the yield of the product obtained in the comparative experiment without adding the ligand is 11%. It is shown that the monodentate phosphine ligand and the O'O-bidentate ligand are the preferred ligands for obtaining the indane compound, and the most preferred is tri-n-butylphosphine.

[0047] Comparative Example 2

[0048] Other steps are the same as in Example 1, except that the nickel catalyst is nickel acetate, and 25 mg of the product is obtained with a yield of 35%.

[0049] Comparative Example 3

[0050] Other steps are the same as in Example 1, except that graphite is used as the anode and carbon fiber is used as the cathode, and 20 mg of the product is obtained with a yield of 27%.

[0051] Comparative Example 4

[0052] Other steps are the same as in Example 1, except that the electrolyte is tetra-n-butylammonium perchlorate, and 48 mg of the product is obtained with a yield of 66%.

[0053] Comparative Example 5

[0054] Other steps are the same as in Example 1, except that triethylamine is added, and 31 mg of the product is obtained with a yield of 43%.

[0055] Comparative Example 6

[0056] Other steps are the same as in Example 1, except that acetonitrile is used as the solvent, and 33 mg of the product is obtained with a yield of 45%.

[0057] Comparative Examples 2-6 show that the solvent, electrode material, additive, nickel catalyst and other factors have a great influence on the yield of the reaction, and the electrolyte is mainly used to improve the conductivity, and has a relatively small influence on the yield.

[0058] Example 2

[0059] The equation of the synthesis method in this example is as follows:

[0060]

[0061] In a one-compartment electrolysis cell, 1,6-diynene of structural formula I-1 (0.2 mmol, 47 mg), monoynene of structural formula II-2 (0.4 mmol, 46 mg), DIPEA (0.24 mmol, 31 mg), NiCl2·DME (0.03 mmol, 6.6 mg), O’O-bidentate ligand of structural formula L2’ (0.06 mmol, 11 μL), and nBu4NBF4(0.3 mmol, 99 mg) were added into 3 mL of DMA solvent, and the mixture was stirred until the solid was completely dissolved. The resulting electrolyte solution was assembled into an electrolysis cell together with a carbon fiber anode (0.15 g) and a foamed glass carbon cathode (0.5 x 2.5 x 0.2 mm 3 ), and the system was sealed. Nitrogen was bubbled into the electrolyte solution for 15 minutes, and then the electrolysis was carried out at room temperature under a constant current of 2 mA for 8 hours. After the electrolysis was completed, the electrodes were cleaned with 10 mL of ethyl acetate twice, and the ethyl acetate cleaning solution was combined with the electrolyte solution in the electrolysis cell, and then washed with 30 mL of deionized water twice. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and column chromatography was used to separate 42 mg of colorless oily product, with a yield of 60%. The proton nuclear magnetic resonance spectrum of the product is shown in Figure 3 , the carbon nuclear magnetic resonance spectrum is shown in Figure 4 , and the nuclear magnetic resonance and mass spectrometry characterization data are as follows: 1 H NMR (400 MHz, CDC13) δ 7.38 (t, J = 7.2 Hz, 2H), 7.33 - 7.26 (m, 3H), 7.10 (s, 1H), 7.05 (s, 1H), 4.22 (q, J = 7.1 Hz, 4H), 3.59 (d, J = 5.8 Hz, 4H), 2.21 (s, 3H), 1.26 (t, J = 7.1 Hz, 6H). 13 CNMR (101 MHz, CDC13) δ 171.87, 142.25, 140.93, 139.26, 137.63, 134.19, 129.35, 128.13, 126.75, 126.02, 125.58, 61.82, 60.65, 40.41, 40.30, 20.56, 14.16. HRMS (EI): exact mass calculated for C 22 H 24 O4[M]+require m / z = 352.1675, found m / z = 352.1672. The characterization data prove that the obtained product is an indane compound with the structure shown in formula III-2.

[0062] Example 3

[0063] The equation of the synthesis method of this example is as follows:

[0064]

[0065] In a one-compartment cell, barbiturate acid-derived 1,6-diynene (shown in structural formula I-2) (46 mg, 0.2 mmol), monoynene shown in structural formula II-1 (0.4 mmol, 51 mg), DIPEA (0.24 mmol, 31 mg), NiCl2·DME (0.03 mmol, 6.6 mg), O’O-bidentate ligand shown in structural formula L2’ (0.06 mmol, 11 μL), and nBu4NBF4(0.3 mmol, 99 mg) were added into 3 mL of DMA solvent, and the mixture was stirred until the solid was completely dissolved. The resulting electrolyte solution was assembled into a cell together with a carbon fiber anode (0.15 g) and a foamed glassy carbon cathode (0.5 x 2.5 x 0.2 mm 3 ), and the system was sealed. Nitrogen gas was bubbled into the electrolyte solution for 15 minutes, and the electrolysis was carried out at room temperature under a constant current of 2 mA for 8 hours. After the electrolysis was completed, the electrodes were cleaned with 10 mL of ethyl acetate by ultrasonic for two times, and the ethyl acetate cleaning solution was combined with the electrolyte solution in the cell, and then washed with 30 mL of deionized water for two times. The organic phase was dried with anhydrous sodium sulfate, and concentrated under reduced pressure. The product was obtained as colorless oil in a yield of 39 mg (58%). The proton nuclear magnetic resonance spectrum of the product is shown in Figure 5 , the carbon nuclear magnetic resonance spectrum is shown in Figure 6 , and the nuclear magnetic resonance and mass spectrometry characterization data are as follows: 1 H NMR (500 MHz, Chloroform-d) δ 7.57-7.52 (m, 2H), 7.42 (dd, J = 14.9, 7.6 Hz, 4H), 7.33 (d, J = 7.3 Hz, 1H), 7.25 (d, J = 6.5 Hz, 1H), 3.65 (d, J = 10.8 Hz, 4H), 3.34 (s, 6H). 13 C NMR (126 MHz, CHLOROFORM-D) δ 172.19, 151.53, 141.27, 140.95, 140.09, 138.47, 128.85, 127.31, 126.79, 124.44, 123.00, 56.47, 44.37, 44.21, 29.23. HRMS (EI): exact mass calculated for C 20 H 18 N2O3[M]+require m / z = 334.1317, found m / z = 334.1314. The characterization data prove that the obtained product is an indane compound with the structure shown in formula III-3.

[0066] Example 4

[0067] The equation of the synthesis method of this embodiment is as follows:

[0068]

[0069] In a one-chamber electrolysis cell, 1,6-diynyl derived from the pharmaceutical intermediate 2,6-dichloro-5-fluoronicotinic acid ethyl ester (70 mg, 0.2 mmol), mono-alkyne shown in structural formula II-1 (0.4 mmol, 51 mg), DIPEA (0.24 mmol, 31 mg), NiCl2·DME (0.03 mmol, 6.6 mg), monodentate phosphine ligand tri-n-butylphosphine shown in structural formula L1 (0.06 mmol, 15 μL) and nBu4NBF4(0.3 mmol, 99 mg) were added into 3 mL of DMA solvent, and the mixture was stirred until the solid was completely dissolved. The obtained electrolyte solution was assembled into an electrolysis cell together with a carbon fiber anode (0.15 g) and a foamed glass carbon cathode (0.5 x 2.5 x 0.2 mm 3 ), and the system was sealed. Nitrogen gas was blown into the electrolyte solution for 15 minutes, and then the electrolysis was carried out at room temperature under a constant current of 2 mA for 8 hours. After the electrolysis was completed, the electrodes were cleaned with 10 mL of ethyl acetate by ultrasonic for two times, and the ethyl acetate cleaning solution was combined with the electrolyte solution in the electrolysis cell, and then washed with 30 mL of deionized water for two times. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by column chromatography to obtain 55 mg of colorless oily product with a yield of 61%. The proton nuclear magnetic resonance spectrum of the product is shown in Figure 7 , the carbon nuclear magnetic resonance spectrum is shown in Figure 8 , the fluorine nuclear magnetic resonance spectrum is shown in Figure 9 , and the nuclear magnetic resonance and mass spectrometry characterization data are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.60-7.53 (m, 3H), 7.43 (dd, J = 7.6, 4.5 Hz, 4H), 7.34 (t, J = 7.3 Hz, 1H), 7.26 (d, J = 7.6 Hz, 1H), 4.22 (q, J = 7.1 Hz, 2H), 3.80-3.66 (m, 4H), 1.23 (t, J = 7.2 Hz, 3H). 13C NMR (101 MHz, Chloroform-d) δ 196.45, 171.67, 153.51 (d, J = 264.1 Hz), 141.03 (d, J = 16.1 Hz), 139.20 (d, J = 164.3 Hz), 134.18 (d, J = 1.7 Hz), 128.89, 127.24, 127.05 (d, J = 68.2 Hz), 125.29, 125.06, 123.14, 67.27, 62.68, 40.98, 40.71, 14.02. 19 F NMR (376 MHz, Chloroform-d) δ -120.28 (d, J = 8.2 Hz). HRMS (EI): exact mass calculated for C 24 H 18 Cl2FNO3[M]+require m / z = 457.0648, found m / z = 457.0642. Characterization data confirmed that the resulting product was an indane compound having the structure shown in Formula III-4.

[0070] Example 5

[0071] The equation for the synthesis method of this example is as follows:

[0072]

[0073] In addition, a series of 1,6-diynes (substituent R 1 , R 2 is an ester group, an amide group, an acyl group, a cyano group) and monoacetylenes (substituent R 3 and R 4 including but not limited to methyl, aryl, substituted aryl, pyridine) were selected as raw materials, and 20 indane compounds were synthesized according to the method of Example 1, and the structures are shown as follows:

[0074]

[0075] The above is a further detailed description of the present application in combination with specific embodiments, but it cannot be determined that the specific implementation of the present application is limited to these descriptions, and it can be fully applied to various fields suitable for the present application. For those skilled in the art, without departing from the concept of the present application, a number of simple deductions or substitutions can be made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present application is not limited to specific details.

Claims

1. A method for preparing indane compounds under electrochemical conditions, characterized in that The method comprises the following steps: dissolving 1,6-diyne, monoacetylene, nickel catalyst, ligand, additive and electrolyte in an organic solvent, stirring until all solids are dissolved, assembling the obtained electrolyte solution into an electrolytic cell, constant current electrolysis under room temperature conditions, the current intensity is 10 mA / mmol based on the substance amount of 1,6-diyne, and after electrolysis, an indane compound is obtained through post-processing; the 1,6-diyne has the following structure shown in formula I, the substituent R 1 and R 2 are one of ester group, amide group, acyl group and cyano group; the monoacetylene has the following structure shown in formula II, the substituent R 3 and R 4 are one of C1-C6 chain and cyclic alkyl group, aryl group and aromatic heterocyclic group; the nickel catalyst is one or any combination of nickel bromide, nickel chloride, nickel chloride dimethoxyethane, nickel acetate, nickel perchlorate, nickel acetylacetone and nickel nitrate; the ligand is a compound having the following structure shown in formula L or L', the substituent R 5 , R 6 are one of C1-C6 chain and cyclic alkyl group and aryl group; and the indane compound has the following structure shown in formula III:

2. The method of claim 1, wherein the indane compound is prepared under electrochemical conditions. The molar ratio of the 1,6-diyn, monoacetylene, nickel catalyst, ligand, additive and electrolyte is 1:(1-3):(0.1-0.3):(0.1-0.5):(0.1-1):(0.5-2).

3. The method of claim 1, wherein the method is performed under electrochemical conditions. The post-treatment is to clean the electrode with ethyl acetate by ultrasonic for two times after electrolysis, combine the ethyl acetate cleaning solution, and combine with the electrolyte solution in the electrolytic cell, then wash with deionized water for two times, dry the obtained organic phase with anhydrous sodium sulfate, concentrate under reduced pressure, and separate by column chromatography to obtain the indane compound.

4. The method of claim 1, wherein the indane compound is prepared under electrochemical conditions. The organic solvent is one or any of acetonitrile, acetone, ethyl acetate, N,N-dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

5. The method of claim 4, wherein the indane compound is prepared under electrochemical conditions. The organic solvent is N,N-dimethylacetamide.

6. The method of claim 1, wherein the indane compound is prepared under electrochemical conditions. The electrolyte is one or any of quaternary ammonium perchlorate, quaternary ammonium tetrafluoroborate, quaternary ammonium hexafluorophosphate, lithium perchlorate and lithium tetrafluoroborate; the additive is one or any of triethylamine, triethanolamine and diisopropylethylamine; the room temperature is 25℃.

7. The method of claim 1, wherein the method is performed under electrochemical conditions. The anode material of the electrolytic cell is one or any of platinum, graphite, carbon fiber, carbon felt, carbon paper and foamed glassy carbon; the cathode material of the electrolytic cell is one or any of foamed nickel, foamed copper, carbon fiber, carbon felt, carbon paper and foamed glassy carbon.

8. The method of claim 7, wherein the method is performed under electrochemical conditions. The anode material is carbon fiber; the cathode material is foamed glassy carbon.

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