A process for the preparation of a cyclohexadienone compound

Abstract

This invention discloses a method for preparing cyclohexadienone compounds. The method uses a vinylamide derivative as a starting material and phenyldimethylsilane as a hydrogen source. Through the combined action of an oxidant and a cobalt salt, the reaction occurs in an organic solvent at a temperature of 10-110°C to generate the corresponding cyclohexadienone compound. This invention uses readily available vinylamide derivatives as starting materials and achieves rapid construction of cyclohexadienone compounds in one step by constructing a ring and two chemical bonds. The reaction conditions are mild, the operation is simple, and it has advantages such as readily available reactants, broad substrate applicability, and easy separation of the target product.

Description

Technical Field

[0001] This invention belongs to the field of catalytic synthesis technology and relates to a method for preparing cyclohexadienone compounds. More specifically, it relates to a method for the dearomatization spirocyclization alkylation reaction of vinylamides catalyzed by cobalt. Background Technology

[0002] As mentioned above, the spirocyclohexadienone skeleton is widely found in natural products and drug molecules, and spirocyclohexadienone has been widely used as a versatile intermediate for constructing important alkaloids and related products. Among them, (-)-cylindricine C and (-)-2-epicylindricine C are structurally unique alkaloids produced by the sea squirt Clavelina cylindrica, possessing cytotoxic (antitumor potential) and antibacterial activities. A total synthetic route was first reported by Marco A. Ciufolini (Angew. Chem. Int. Ed., 2004, 43, 4336) in 2004. Furthermore, the spirocyclohexadienone skeleton can also serve as an intermediate for the synthesis of the muscarinic receptor antagonist (-)-TAN1251A, which is commonly used as a mydriatic or antispasmodic / anti-ulcer agent. TAN1251A was isolated from *Penicillium tomocarpa* RA-89 by a research group at Takeda Chemical Industries, Ltd., and the total synthetic route of (-)-TAN1251A was first reported by Duncan J. Wardrop (Org. Lett. 2001, 3, 1053-1056) in 2001. Furthermore, Duncan J. Wardrop's group discovered that the intermediate FR901483 shares a common spirocyclohexadienone skeleton with the (-)-TAN1251A intermediate. FR901483 is a potent immunosuppressant with bioactivity that inhibits purine nucleotide biosynthesis.

[0003] Also in 2001 (Org. Lett. 2001, 3, 2353-2356), the route for synthesizing FR901483 via an intermediate from a spirocyclohexadienone skeleton was first reported. The specific synthetic route is as follows: .

[0004] Dearomatization, spirocyclic alkylation, and hydroalkylation reactions can efficiently synthesize a series of cyclic compounds. Different spirocyclic products can be obtained by changing the substrate structure or selecting a suitable metal catalyst. Intramolecular dearomatization of phenolic compounds has attracted the attention of chemists for the direct and efficient synthesis of spirocyclohexadienone molecules. Various transition metal catalytic and photocatalytic dearomatization reactions of phenols have become increasingly mature. Meanwhile, cobalt-catalyzed hydrogen-functionalization reactions of alkenes have also been widely reported. Although there are many excellent works on cobalt-catalyzed dearomatization of phenols, most of the known reports use alkenylphenols and alkynes as substrates, while studies on the synthesis of spirocyclic products from alkenylamide phenols are rarely reported.

[0005] Based on this, we envision utilizing the C4 position of phenols as a nucleophilic site. Cobalt hydrogen reacts with alkenes via metal-hydride hydrogen atom transfer and radical-polar cross-linking to generate alkylcobalt, which then reacts with the C4 phenol to yield a dearomatized product. Using vinylamide derivatives as raw materials, we developed a cobalt-catalyzed dearomatization spirocyclic alkylation reaction to rapidly synthesize structurally unique cyclohexenediones, which has significant research value for establishing potentially bioactive molecular libraries. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing cyclohexadienone compounds, which utilizes readily available reaction materials to synthesize cyclohexadienone compounds in one step through a cobalt-catalyzed dearomatization spirocyclization alkylation reaction of vinylamide derivatives.

[0007] The technical solution adopted in this invention is as follows: A method for preparing a cyclohexadienone compound, using a vinylamide derivative of Formula I as a raw material, reacting it in an organic solvent at a temperature of 10-110°C under the combined action of phenyldimethylsilane as a hydrogen source, an oxidant, and a cobalt salt. After the reaction, post-treatment yields the cyclohexadienone compound of Formula II. The general reaction formula is as follows: ; In the formula: R 1 It is one of C1-C4 alkyl, C1-C4 alkoxy, phenyl, or phenyl-substituted C1-C4 alkyl; R 2 It is one of C1-C4 alkyl, substituted or unsubstituted phenyl, halogen or thiophene, wherein the substituent on the benzene ring of the substituted phenyl is C1-C4 alkyl, C1-C4 alkoxy, halogen, cyano, trifluoromethyl or trifluoromethoxy.

[0008] Furthermore, the organic solvent is selected from dichloromethane, dichloroethane, toluene, m-xylene, methanol, ethanol, dimethyl sulfoxide, etc. N , NThe organic solvent is selected from any one of dimethylformamide, tetrahydrofuran, acetonitrile, or 1,4-dioxane, and the volume ratio of the organic solvent to the molar ratio of the vinylamide derivative is 5 to 30:1, with volume in milliliters and molar in millimoles.

[0009] Furthermore, the volume ratio of the organic solvent to the molar ratio of the vinylamide derivative is 8-15:1, with volume measured in milliliters and molars in millimoles.

[0010] Furthermore, the cobalt catalyst is selected from any one of [cobalt]-1, [cobalt]-2, and [cobalt]-3, and their structures are as follows: ; The molar ratio of the vinylamide derivative to the cobalt catalyst is 1:0.1~0.5, preferably 1:0.1~0.2.

[0011] Furthermore, the oxidant is selected from tert-butyl peroxybenzoate, N -Any of fluorobisbenzenesulfonamide, potassium peroxymonosulfonate, and [oxygen]-1, wherein the structure of [oxygen]-1 is as follows: ; The molar ratio of vinylamide derivative to oxidant is 1:1.5-3.

[0012] Furthermore, the hydrogen source is selected from any one of phenyldimethylsilane, phenylmethylsilane, phenylsilane, and 1,1,3,3-tetramethyldisiloxane, and the molar ratio of the vinylamide derivative to the hydrogen source is 1:1.5-3.

[0013] Furthermore, the reaction temperature is 20-40℃, preferably 30±2℃, and the reaction time is 6-15 h, preferably 8-12 h.

[0014] Further, the post-processing steps are as follows: after the reaction is completed, the solvent is removed by rotary evaporation and the target product is obtained by column chromatography; the mobile phase of column chromatography is a mixture of petroleum ether and ethyl acetate with a volume ratio of 1~10:1.

[0015] In this invention, [cobalt]-1, [cobalt]-2, and [cobalt]-3 are all known compounds, and their preparation methods were first reported by Qian Zhang (Angew. Chem. Int. Ed. 2021, 60, 25949) in 2021.

[0016] In this invention, [oxygen]-1 is a known compound, and its preparation method was reported by Jie Liu (ChemCatChem 2024, 16,e202301750) in 2024.

[0017] By employing the above-described technology, the beneficial effects of the present invention compared to the prior art are as follows: This invention enables the efficient one-step synthesis of cyclohexadienone compounds from vinylamide derivatives via a dearomatization-spirocyclic alkylation reaction under the combined action of a cobalt catalyst, oxidant, and hydrogen source. The reaction has the advantages of readily available and simple raw materials, easy operation, mild conditions, good functional group tolerance, and broad substrate versatility. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0019] Blank Example 1: The vinylamide derivative 1a-1l used in this invention can be synthesized according to the following reaction route: ; Step 1: In a dry flask, add NaOMe (4.0 equiv) and paraformaldehyde (4.0 equiv) to a methanol solution of aniline derivative (1.0 equiv). Reflux for 4 h. After cooling to room temperature, slowly add NaBH4 (3.5 equiv) in four portions. Then reflux the mixture until the reaction is complete. Concentrate under reduced pressure, dilute with water, and extract three times with ethyl acetate. Dry the combined organic layers with Na2SO4 and concentrate under reduced pressure. Elute with petroleum ether / ethyl acetate (5:1, v / v), and purify by silica gel column chromatography to obtain compound S1.

[0020] Step 2: In a dry flask, add DCC (1.3 equiv) and DMAP (0.15 equiv) to a DCM solution of compound S1 (1.0 equiv). Stir the solution at 0°C. Slowly add a carboxylic acid compound (1.3 equiv) to the above solution and stir overnight. Filter to remove the precipitate, and concentrate the filtrate under reduced pressure. Elute with petroleum ether / ethyl acetate (5:1, v / v), and purify by silica gel column chromatography to obtain compound S2.

[0021] Step 3: Take a dry Shrek bottle and, under a nitrogen atmosphere, add a DCM solution of BBr3 (3.6 equiv) to a DCM solution of compound S2 (1.0 equiv) at 0°C. Stir at the above temperature until the reaction is complete. Quench the reaction with a saturated NaHCO3 aqueous solution at 0°C. Dilute with water and extract with DCM. Dry the combined organic layers with Na2SO4 and concentrate under reduced pressure. Perform silica gel column chromatography, eluting with petroleum ether / ethyl acetate (2:1, v / v) and dichloromethane to give the vinylamide derivative 1a-1m.

[0022] Following the above synthetic route, the aniline derivatives, compounds S1, S2, and the final product 1a-1m all have the same substituent R on the corresponding benzene ring. The carboxylic acid compounds, compound S2, and the final product 1a-1m all have the same substituent R'.

[0023] The raw material, vinylamide derivative 1m, is a known compound, produced by Qingmin Wang ( Org. Lett. The preparation method was reported in 2014 (2014, 16, 5914-5917).

[0024] Example 1: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1a (50.6 mg, 0.2 mmol), [cobalt]-1 (4.0 mg, 0.033 mmol), and tert-butylperoxybenzoate (0.4 mmol) were added sequentially to a dry Schlenk tube. Then, dichloromethane (2.0 mL) was added via syringe, and the reaction tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2a in 90% yield.

[0025] NMR of compound 2a: 1 H NMR (500 MHz, CDCl3) d 7.30-7.24 (m, 3H), 7.14-7.09(m, 2H), 6.85 (dd, J = 10.1, 3.1 Hz, 1H), 6.48 (dd, J = 10.2, 3.1 Hz, 1H), 6.43 (dd, J = 10.1, 2.0 Hz, 1H), 6.06 (dd, J = 10.2, 2.0 Hz, 1H), 3.69 (dd, J = 10.7, 8.7 Hz, 1H), 3.06 (dd, J = 16.9, 10.8 Hz, 1H), 2.91 (dd, J= 16.8,8.8 Hz, 1H), 2.73 (s, 3H). 13 C NMR (125 MHz, CDCl3) d 184.2, 173.9, 148.8,146.2, 135.0, 132.0, 131.5, 128.7, 128.2, 127.7, 66.3, 48.0, 34.3, 26.9. MS m / z (ESI+): Calculated for C 16 H 16 NO2 + ([M+H)) + ) 254.1176, found 254.1182. Vinylamide derivative 1a is a known compound in ( Org. Lett. This has been reported in the literature (2014, 16, 5914-5917), and is provided here. 1 H NMR data: 1 H NMR (500 MHz, CDCl3) δ 8.41 (s, 1H), 7.69(d, J = 15.6 Hz, 1H), 7.33-7.31 (m, 2H), 7.30-7.26 (m, 3H), 7.15-7.09 (m,2H), 7.08-7.01 (m, 2H), 6.45 (d, J = 15.6 Hz, 1H), 3.43 (s, 3H). Example 2: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1b (53.5 mg, 0.2 mmol), [cobalt]-1 (10.4 mg, 0.033 mmol), and N-fluorobisbenzenesulfonamide (126 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2b in 70% yield.

[0026] The NMR data for compound 2b are as follows: 1 H NMR (500 MHz, CDCl3) d 7.22-7.10 (m, 4H), 6.88 (dd, J = 10.1, 3.1 Hz, 1H), 6.37 (dd, J = 2.6, 1.7 Hz, 1H), 6.36-6.34 (m,1H), 6.12 (dd, J = 10.3, 2.0 Hz, 1H), 3.98 (dd, J = 9.1, 6.2 Hz, 1H), 3.02(dd, J = 17.4, 9.1 Hz, 1H), 2.89 (dd, J = 17.4, 6.2 Hz, 1H), 2.71 (s, 3H), 2.20 (s, 3H). 13 C NMR (125 MHz, CDCl3) d 184.04, 174.24, 149.15, 147.26,136.44, 135.92, 131.25, 131.07, 130.65, 127.84, 126.74, 126.49, 65.56, 42.48,36.67, 26.59, 20.39.MS m / z (ESI+): Calculated for C 17 H 18 NO2+ ([M+H)) + )268.1332, found 268.1337. Following the synthetic steps of Blank Example 1, the yield of vinylamide derivative 1b was 82%, a white solid, mp 171-172. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.73 (s, 1H), 7.69 (d, J =15.5 Hz, 1H), 7.26-7.14 (m, 4H), 7.14-7.10 (m, 2H), 6.87-6.79 (m, 2H), 6.25(d, J = 15.5 Hz, 1H), 3.23 (s, 3H), 2.32 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d HRMS m / z (ESI+): Calculated for C 17 H 18 NO2 + ([M+H)) + )268.1332, found 268.1340. Example 3: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1c (56.7 mg, 0.2 mmol), [cobalt]-1 (10.4 mg, 0.033 mmol), and potassium peroxymonosulfonate (138.5 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 12 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2c in 82% yield.

[0027] The NMR data for compound 2c are as follows: 1 H NMR (500 MHz, CDCl3) d 7.26–7.20 (m, 1H), 7.12 (d, J = 7.5 Hz, 1H), 6.91 (t, J = 7.4 Hz, 1H), 6.85 (dd, J = 10.1, 3.0 Hz, 1H), 6.82 (d, J = 8.3 Hz, 1H), 6.48 (dd, J = 10.2, 3.0 Hz, 1H), 6.31 (dd, J =10.1, 1.8 Hz, 1H), 6.05 (dd, J = 10.2, 1.8 Hz, 1H), 4.16 (t, J = 9.2 Hz, 1H), 3.71 (s, 3H), 3.06 (dd, J = 17.1, 9.2 Hz, 1H), 2.84 (dd, J = 17.1, 9.2 Hz,1H), 2.71 (s, 3H). 13 C NMR (125 MHz, CDCl3) dMS m / z (ESI+): Calculated for Calculated for C 17 H 18 NO3 + ([M+H)) + )284.1281, found 284.1278. Following the synthesis steps of blank example 1, the vinylamide derivative 1c showed an NMR yield of 92%, was a white solid, and had an mp of 189-190. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.71 (s, 1H), 7.67 (d, J =15.7 Hz, 1H), 7.31 (t, J = 7.6 Hz, 1H), 7.23 (d, J = 7.2 Hz, 1H), 7.11 (d, J = 8.6 Hz, 2H), 7.00 (d, J = 8.3 Hz, 1H), 6.89 (t, J = 7.4 Hz, 1H), 6.84 (d, J = 8.5 Hz, 2H), 6.45 (d, J = 15.7 Hz, 1H), 3.75 (s, 3H), 3.23 (s, 3H). 13 C NMR (125 MHz, DMSO-) d 6) d HRMS m / z (ESI+): Calculatedfor C 17 H 18 NO3 + ([M+H)) +) 284.1281, found 284.1288. Example 4: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1d (66.2 mg, 0.2 mmol), [cobalt]-2 (5.0 mg, 0.033 mmol), and [oxygen]-1 (106 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of methylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 10 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2d in 73% yield.

[0028] 2d NMR of the compound: 1 H NMR (500 MHz, CDCl3) d 7.54 (dd, J = 8.0, 1.3 Hz, 1H), 7.32 (td, J = 7.5, 1.3 Hz, 1H), 7.25 (dd, J = 7.9, 1.7 Hz, 1H), 7.15 (td, J =7.7, 1.7 Hz, 1H), 6.93 (dd, J = 10.1, 3.1 Hz, 1H), 6.38 (dd, J = 10.1, 2.0Hz, 1H), 6.34 (dd, J = 10.3, 3.1 Hz, 1H), 6.16 (dd, J = 10.3, 2.0 Hz, 1H), 4.34 (dd, J = 9.1, 6.9 Hz, 1H), 3.03 (dd, J = 17.4, 9.1 Hz, 1H), 2.86 (dd, J = 17.5, 6.9 Hz, 1H), 2.71 (s, 3H). 13C NMR (125 MHz, CDCl3) d MS m / z (ESI+): Calculated for C 16 H 15 BrNO2 + ([M+H)) + ) 332.0281,found 332.0281. Following the synthesis steps of blank example 1, the vinylamide derivative showed an 88% NMR yield on day 1, and was a white solid with mp 195-196. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.74 (s, 1H), 7.73 (d, J =15.5 Hz, 1H), 7.66 (d, J = 7.8 Hz, 1H), 7.35-7.31 (m, 2H), 7.28-7.24 (m, 1H), 7.15-7.12 (m, 2H), 6.85-6.81 (m, 2H), 6.37 (d, J = 15.5 Hz, 1H), 3.24 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d 164.8, 157.2, 138.5, 134.8, 134.7, 133.6,131.6, 128.9, 128.8, 128.1, 124.5, 122.8, 116.5, 37.8. HRMS m / z (ESI+):Calculated for C 16 H 15 BrNO2 + ([M+H)) + ) 332.0281, found 332.0287. Example 5: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1e (53.5 mg, 0.2 mmol), [cobalt]-2 (5.0 mg, 0.033 mmol), and potassium peroxymonosulfonate (138.5 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the reaction tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of methylphenylsilane (0.4 mmol), and the mixture was stirred at 30 °C for another 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2e in 75% yield.

[0029] NMR of compound 2e: 1 H NMR (500 MHz, CDCl3) d 7.16 (t, J = 7.6 Hz, 1H), 7.06(d, J = 7.5 Hz, 1H), 6.91 (d, J = 7.8 Hz, 2H), 6.83 (dd, J = 10.1, 3.1 Hz, 1H), 6.48 (dd, J = 10.2, 3.1 Hz, 1H), 6.42 (dd, J = 10.1, 2.0 Hz, 1H), 6.06(dd, J = 10.2, 2.0 Hz, 1H), 3.64 (dd, J = 10.3, 8.9 Hz, 1H), 3.02 (dd, J =16.9, 10.6 Hz, 1H), 2.88 (dd, J = 17.0, 8.7 Hz, 1H), 2.72 (s, 3H), 2.29 (s, 3H). 13 C NMR (125 MHz, CDCl3) dMS m / z (ESI+): Calculated for C 17 H 18 NO2 + ([M+H)) + ) 268.1332, found 268.1327. Following the synthesis steps of blank example 1, the vinylamide derivative 1e showed an NMR yield of 68%, was a white solid, and mp 161-162. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.73 (s, 1H), 7.45 (d, J =15.6 Hz, 1H), 7.22 (t, J = 7.5 Hz, 1H), 7.19-7.13 (m, 3H), 7.13-7.10 (m, 2H), 6.87-6.82 (m, 2H), 6.35 (d, J = 15.6 Hz, 1H), 3.23 (s, 3H), 2.26 (s, 3H). 13 CNMR (125 MHz, DMSO- d 6) d HRMS m / z (ESI+):Calculated for C 17 H 18 NO2 + ([M+H)) + ) 268.1332, found 268.1335. Example 6: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1f (56.7 mg, 0.2 mmol), [cobalt]-2 (5.0 mg, 0.033 mmol), and potassium peroxymonosulfonate (138.5 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2f in 68% yield.

[0030] Compound 2f NMR: 1 H NMR (500 MHz, CDCl3) d 7.20 (t, J = 8.0 Hz, 1H), 6.84(dd, J = 10.1, 3.1 Hz, 1H), 6.79 (dd, J = 8.2, 2.2 Hz, 1H), 6.71 (d, J = 7.7Hz, 1H), 6.66-6.62 (m, 1H), 6.48 (dd, J = 10.2, 3.1 Hz, 1H), 6.43 (dd, J =10.1, 2.0 Hz, 1H), 6.08 (dd, J = 10.2, 2.0 Hz, 1H), 3.76 (s, 3H), 3.66 (dd, J = 10.6, 8.8 Hz, 1H), 3.02 (dd, J = 16.9, 10.8 Hz, 1H), 2.88 (dd, J = 16.9,8.7 Hz, 1H), 2.72 (s, 3H). 13 C NMR (125 MHz, CDCl3) dMS m / z (ESI+): Calculated for C 17 H 18 NO3 + ([M+H)) + ) 284.1281,found 284.1284. Following the synthesis steps of blank example 1, the vinylamide derivative 1f showed an NMR yield of 92%, was a white solid, and had an mp of 156-157. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.73 (s, 1H), 7.45 (d, J =15.6 Hz, 1H), 7.25 (t, J = 7.8 Hz, 1H), 7.14-7.10 (m, 2H), 6.96-6.88 (m, 3H), 6.86-6.82 (m, 2H), 6.35 (d, J = 15.6 Hz, 1H), 3.72 (s, 3H), 3.23 (s, 3H). 13 CNMR (125 MHz, DMSO- d 6) d HRMS m / z (ESI+):Calculated for C 17 H 18 NO3 + ([M+H)) + ) 284.1281, found 284.1289. Example 7: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, 1 g (66.2 mg, 0.2 mmol) of a vinylamide derivative, 5.0 mg (0.033 mmol) of [cobalt]-2, and 126 mg (0.4 mmol) of N-fluorobisbenzenesulfonamide were added sequentially to a dry Schlenk tube. Dichloroethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 minutes, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 hours. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give 2 g of product, with a yield of 92%.

[0031] 2g of compound NMR: 1 H NMR (500 MHz, CDCl3) d 78.15 (dd, J = 7.9, 1.2 Hz,1.3H), 8.14-8.11 (m, 1H), 8.00-7.50 (m, 2.3H), 7.64 (d, J = 7.7 Hz, 1.3H),7.60-7.55 (m, 2.6H), 7.47 (t, J = 7.7 Hz, 1H), 7.34 (td, J = 7.6, 1.1 Hz,1H), 7.21-7.13 (m, 5H), 7.07-7.03 (m, 2H), 6.98-6.93 (m, 2H), 6.75-6.71 (m,2.6H), 6.64 (d, J = 10.3 Hz, 1H), 6.64-6.60 (m, 2H), 6.56 (d, J = 10.1 Hz, 1H), 6.22 (d, J = 10.3 Hz, 1.3H), 3.97 (dd, J = 12.0, 8.6 Hz, 1.3H), 3.71(dd, J = 12.0, 8.7 Hz, 1H), 3.18 (dd, J = 16.9, 12.1 Hz, 1.3H), 3.11 (dd,J =16.9, 12.1 Hz, 1H), 3.00 (dd, J = 16.9, 8.5 Hz, 1.3H), 2.87 (dd, J = 16.9,8.5 Hz, 1H), 2.84 (s, 3H), 2.60 (s, 3.9H). 13 C NMR (125 MHz, CDCl3) d 182.9,182.9, 174.7, 174.3, 149.6, 146.6, 142.5, 139.6, 134.7, 133.8, 133.3, 132.9,132.5, 132.4, 131.8, 131.2, 130.1, 128.8, 128.6, 128.4, 128.1, 127.9, 127.9,127.4, 127.0, 126.2, 124.7, 69.9, 68.2, 53.4, 50.0, 34.2, 33.9, 27.6, 27.0.MS m / z (ESI+): Calculated for C 20 H 18 NO2 + ([M+H)) + ) 304.1332, found 304.1335. Following the synthesis steps of blank example 1, 1 g of the vinylamide derivative showed an NMR yield of 94%, and was a white solid with mp 226-227. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 10.59 (s, 1H), 8.25 (d, J = 8.2 Hz, 1H), 7.63 (d, J = 8.1 Hz, 1H), 7.60-7.57 (m, 1H), 7.56-7.51 (m,2H), 7.35 (d, J = 7.9 Hz, 1H), 7.26-7.21 (m, 3H), 7.21-7.17 (m, 2H), 6.94 (d, J = 7.9 Hz, 1H), 6.12 (d, J = 15.6 Hz, 1H), 3.32 (s, 3H).13 C NMR (125 MHz, DMSO- d 6) d 166.2, 153.9, 141.04, 1345.0, 131.4, 130.7, 130.0, 129.3, 128.2,127.9, 127.2, 125.8, 125.7, 123.4, 122.5, 119.0, 108.2, 37.7. HRMS m / z (ESI+): Calculated for C 20 H 18 NO2 + ([M+H)) + ) 304.1332, found 304.1335. Example 8: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1h (57.5 mg, 0.2 mmol), [cobalt]-2 (5.0 mg, 0.033 mmol), and tert-butylperoxybenzoate (0.4 mmol) were added sequentially to a dry Schlenk tube. Tetrahydrofuran (2.0 mL) was then added via syringe, and the reaction tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of dimethylphenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2h in 90% yield.

[0032] 2h NMR of compound: 1 H NMR (500 MHz, CDCl3) d 7.28–7.24 (m, 2H), 7.06 (d, J =8.5 Hz, 2H), 6.83 (dd, J = 10.1, 3.1 Hz, 1H), 6.48-6.45 (m, 1H), 6.44 (dd, J = 8.2, 1.9 Hz, 1H), 6.10 (dd, J = 10.2, 1.9 Hz, 1H), 3.66 (dd, J= 10.5, 8.9Hz, 1H), 2.98 (dd, J = 16.9, 10.8 Hz, 1H), 2.89 (dd, J = 17.0, 8.7 Hz, 1H),2.73 (s, 3H. 13 C NMR (125 MHz, CDCl3) d 183.9, 173.3, 148.5, 145.7, 134.2,133.6, 132.2, 131.8, 129.0, 128.9, 66.1, 47.5, 34.3, 26.9. MS m / z (ESI+): Calculated for C 16 H 15 ClNO2 + ([M+H)) + ) 288.0786, found 288.0787. Following the synthesis steps of blank example 1, the vinylamide derivative showed an NMR yield of 85% after 1 hour, and was a white solid with mp 191-192. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.74 (s, 1H), 7.47 (d, J =15.6 Hz, 1H), 7.40 (s, 4H), 7.14-7.10 (m, 2H), 6.85-6.81 (m, 2H), 6.37 (d, J = 15.6 Hz, 1H), 3.23 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d 165.1, 157.1,139.2, 134.9, 134.4, 134.2, 129.7, 129.4, 128.9, 120.3, 116.5, 37.7. HRMS m / z(ESI+): Calculated for C 16 H 15 ClNO2 + ([M+H)) + ) 288.0786, found 288.0786. Example 9: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1i (55.7 mg, 0.2 mmol), [cobalt]-2 (5.0 mg, 0.033 mmol), and [oxygen]-1 (106 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Methanol (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of 1,1,3,3-tetramethyldisiloxane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2i in 55% yield.

[0033] Compound 2i NMR: 1 H NMR (500 MHz, CDCl3) d 7.60 (d, J = 8.1 Hz, 2H), 7.27(d, J = 8.4 Hz, 2H), 6.86 (dd, J = 10.1, 3.1 Hz, 1H), 6.48-6.42 (m, 2H), 6.10(dd, J = 10.2, 2.0 Hz, 1H), 3.74 (dd, J = 10.7, 8.7 Hz, 1H), 3.03 (dd, J =16.9, 10.7 Hz, 1H), 2.93 (dd, J = 16.9, 8.7 Hz, 1H), 2.74 (s, 3H). 13 C NMR (125 MHz, CDCl3) d Calculated for C 17 H 15 N2O2 + ([M+H)) +)279.1128, found 279.1130. Following the synthesis steps of blank example 1, the vinylamide derivative 1i showed an NMR yield of 90%, was a white solid, and had an mp of 206-207. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.75 (s, 1H), 7.79 (d, J =8.0 Hz, 2H), 7.57 (d, J = 8.0 Hz, 2H), 7.53 (d, J = 15.6 Hz, 1H), 7.14-7.10(m, 2H), 6.87-6.79 (m, 2H), 6.50 (d, J = 15.6 Hz, 1H), 3.24 (s, 3H). 13 C NMR (125 MHz, DMSO-) d 6) d 164.8, 157.2, 139.8, 138.7, 134.7, 133.2, 128.9, 128.7,123.1, 119.1, 116.5, 111.9, 37.8. HRMS m / z (ESI+): Calculated for C 17 H 15 N2O2 + ([M+H)) + ) 279.1128, found 279.1131. Example 10: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1j (64.3 mg, 0.2 mmol), [cobalt]-1 (4.0 mg, 0.033 mmol), and [oxygen]-1 (106 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Acetonitrile (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of 1,1,3,3-tetramethyldisiloxane (0.4 mmol). The resulting mixture was stirred at 30 °C for 16 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 to 1:1) as eluent to give product 2j in 50% yield.

[0034] Compound 2j NMR: 1 H NMR (500 MHz, CDCl3) d 7.56 (d, J = 8.1 Hz, 2H), 7.27(d, J = 8.4 Hz, 2H), 6.86 (dd, J = 10.1, 3.1 Hz, 1H), 6.46 (dd, J = 10.1, 2.5Hz, 2H), 6.10 (dd, J = 10.2, 2.0 Hz, 1H), 3.75 (dd, J = 10.6, 8.7 Hz, 1H), 3.05 (dd, J = 16.9, 10.8 Hz, 1H), 2.94 (dd, J = 16.9, 8.7 Hz, 1H), 2.74 (s,3H). 13 C NMR (125 MHz, CDCl3) d 183.8, 173.2, 148.3, 145.4, 139.2, 132.4,131.9, 130.5 (q, J = 32.5 Hz), 128.1, 125.7 (q, J = 3.8 Hz), 123.7 (q, J =270.0 Hz), 66.0, 47.7, 34.2, 26.98.19 F NMR (377 MHz, CDCl3) d -62.7. MS m / z(ESI+): Calculated for C 17 H 15 F3NO2 + ([M+H)) + ) 322.1049, found 322.1045. Vinylamide derivative 1j, white solid, mp 184-185 o C, the NMR data are as follows: 1 H NMR (500MHz, DMSO- d 6) d 9.76 (s, 1H), 7.69 (d, J = 8.0 Hz, 2H), 7.62-7.52 (m, 3H),7.13 (d, J = 8.2 Hz, 2H), 6.84 (d, J = 8.2 Hz, 2H), 6.49 (d, J = 15.6 Hz, 1H), 3.24 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d 164.9, 157.2, 139.3, 138.9,134.7, 129.7 (q, J = 31.3 Hz), 128.9, 128.6, 126.2 (q, J = 3.8 Hz), 124.4 (q, J = 271.3 Hz), 122.4, 116.5, 37.7. 19 F NMR (377 MHz, DMSO- d 6) d -61.3. HRMS m / z (ESI+): Calculated for C 17 H 15 F3NO2 + ([M+H)) + ) 322.1049, found 322.1052. Example 11: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1k (64.3 mg, 0.2 mmol), [cobalt]-1 (4.0 mg, 0.033 mmol), and [cobalt]-1 were added sequentially to a dry Schlenk tube. N - Fluorobis(benzenesulfonamide) (126 mg, 0.4 mmol). Toluene (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of phenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2K, in 78% yield.

[0035] 2k NMR of the compound: 1 H NMR (500 MHz, CDCl3) d 7.18–7.10 (m, 4H), 6.84 (dd, J = 10.1, 3.1 Hz, 1H), 6.50-6.41 (m, 2H), 6.11 (dd, J = 10.2, 2.0 Hz, 1H), 3.70(dd, J = 10.8, 8.7 Hz, 1H), 3.00 (dd, J = 16.9, 10.7 Hz, 1H), 2.91 (dd, J =16.9, 8.7 Hz, 1H), 2.73 (s, 3H). 13 C NMR (125 MHz, CDCl3) d 183.9, 173.3,148.9, 148.5, 145.6, 133.8, 132.3, 131.8, 129.1, 121.0, 120.3 (q, J = 256.3Hz), 66.1, 47.4, 34.4, 26.9. 19 F NMR (377 MHz, CDCl3) d -57.9. MS m / z (ESI+):Calculated for C 17 H 15 F3NO3 +([M+H)) + ) 338.0999, found 338.0999. Following the synthesis steps of blank example 1, the vinylamide derivative showed a 99% NMR yield at 1K, and was a white solid with mp 175-176. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.75 (s, 1H), 7.54-7.48 (m, 3H), 7.32 (d, J = 8.2 Hz, 2H), 7.14-7.10 (m, 2H), 6.86-6.81 (m, 2H), 6.38(d, J = 15.7 Hz, 1H), 3.23 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d 165.1, 157.1,149.3, 138.9, 134.8, 134.6, 129.9, 128.9, 121.8, 120.8, 120.4 (q, J = 255.0Hz), 116.5, 37.7. 19 F NMR (377 MHz, DMSO- d 6) d -56.8. HRMS m / z (ESI+):Calculated for C 17 H 15 F3NO3 + ([M+H)) + ) 338.0999, found 338.1000. Example 12: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, 1 μL of vinylamide derivative (51.8 mg, 0.2 mmol), [cobalt]-1 (4.0 mg, 0.033 mmol), and [oxygen]-1 (106 mg, 0.4 mmol) were added sequentially to a dry Schlenk tube. Dichloromethane (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of phenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 8 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2 μL, in 92% yield.

[0036] NMR of compound 2l: 1 H NMR (500 MHz, CDCl3) d 7.12–7.09 (m, 1H), 6.85 (dd, J = 5.0, 3.6 Hz, 1H), 6.76 (d, J = 3.5 Hz, 1H), 6.72 (dd, J = 10.1, 3.1 Hz, 1H), 6.46 (dd, J = 10.2, 3.1 Hz, 1H), 6.43 (dd, J = 10.1, 1.9 Hz, 1H), 6.07(dd, J = 10.2, 1.9 Hz, 1H), 3.88-3.81 (m, 1H), 2.93 (s, 1H), 2.91 (d, J = 3.5Hz, 1H), 2.67 (s, 3H). 13 C NMR (125 MHz, CDCl3) d 184.2, 172.9, 148.1, 145.3,138.0, 132.9, 131.9, 127.0, 125.1, 66.2, 43.7, 35.9, 27.0. MS m / z (ESI+):Calculated for C 14 H 14 SNO2 + ([M+H)) +) 260.0740, found 260.0743. Following the synthesis steps of blank example 1, the vinylamide derivative 1L showed an NMR yield of 88%, and was a white solid with an mp of 213-214. o C, the NMR data are as follows: 1 H NMR (500 MHz, DMSO- d 6) d 9.75 (s, 1H), 7.63 (d, J =15.3 Hz, 1H), 7.52 (d, J = 4.9 Hz, 1H), 7.33 (d, J = 2.9 Hz, 1H), 7.14-7.09(m, 2H), 7.08-7.03 (m, 1H), 6.87-6.81 (m, 2H), 6.08 (d, J = 15.3 Hz, 1H), 3.21 (s, 3H). 13 C NMR (125 MHz, DMSO- d 6) d 165.0, 157.1, 140.2, 134.9, 133.7,131.4, 128.9, 128.8, 128.6, 118.1, 116.5, 37.6. HRMS m / z (ESI+): Calculatedfor C 14 H 14 SNO2 + ([M+H)) + ) 260.0740, found 260.0745. Example 13: A method for preparing a cyclohexadienone compound Under a nitrogen atmosphere, vinylamide derivative 1m (51.8 mg, 0.2 mmol), [cobalt]-1 (4.0 mg, 0.033 mmol), and tert-butylperoxybenzoate (76 μL, 0.4 mmol) were added sequentially to a dry Schlenk tube. Tetrahydrofuran (2.0 mL) was then added via syringe, and the tube was sealed with a Teflon cap. The reaction mixture was stirred at 30 °C for 30 min, followed by the addition of phenylsilane (0.4 mmol). The resulting mixture was stirred at 30 °C for 14 h. After the reaction was complete, the reaction mixture was washed with saturated sodium hydroxide aqueous solution, diluted with water, and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether / ethyl acetate (v / v = 2:1 ~ 1:1) as eluent to give product 2m in 88% yield.

[0037] 2m NMR of compound: 1 H NMR (500 MHz, CDCl3) d .27-7.24 (m, 6H), 7.23-7.20 (m,2H), 7.10-7.07 (m, 2H), 6.65 (dd, J = 10.1, 3.1 Hz, 1H), 6.35 (dd, J = 10.2, 3.1 Hz, 1H), 6.24 (dd, J = 10.1, 2.0 Hz, 1H), 5.85 (dd, J = 10.2, 2.0 Hz, 1H), 4.52 (d, J = 14.9 Hz, 1H), 4.24 (d, J = 14.9 Hz, 1H), 3.67 (dd, J =10.8, 8.6 Hz, 1H), 3.12 (dd, J = 17.0, 10.9 Hz, 1H), 2.97 (dd, J = 17.0, 8.5Hz, 1H). 13 C NMR (125 MHz, CDCl3) d184.4, 173.9, 148.8, 146.5, 137.6, 134.8,131.1, 130.6, 128.6, 128.6, 128.5, 128.3, 127.8, 127.8, 66.6, 48.6, 45.2,34.3. MS m / z (ESI+): Calculated for C 22 H 20 NO2 + ([M+H)) + ) 330.1489, found330.1498. Vinylamide derivative 1m is a known compound in ( Org. Lett. This has been reported in the literature (2014, 16, 5914-5917), and is provided here. 1 H NMR data: 1 H NMR (500 MHz, DMSO- d 6) d 9.71 (s, 1H), 7.58 (d, J = 15.6 Hz, 1H), 7.39-7.32 (m, 5H), 7.31-7.28 (m, 2H), 7.25-7.19 (m,3H), 6.96 (d, J = 8.5 Hz, 2H), 6.76 (d, J = 8.5 Hz, 2H), 6.38 (d, J = 15.6 Hz, 1H), 4.94 (s, 2H). The experimental results corresponding to the specific cyclohexadienone compounds synthesized in Examples 1-13 are listed in Tables 1.1, 1.2, and 1.3: Table 1.1 Results of cobalt-catalyzed synthesis of cyclohexadienone [a] .

[0038] Table 1.2 Results of cobalt-catalyzed synthesis of cyclohexadienone [a] .

[0039] Table 1.3 Results of cobalt-catalyzed synthesis of cyclohexadienone [a] .

[0040] [a] The reaction conditions are shown in the examples; [b] Separation yield.

[0041] The specific structures of [cobalt]-1, [cobalt]-2, [cobalt]-3, and [oxygen]-1 used in the above preparation method are as follows: .

[0042] The above descriptions are merely several specific embodiments of the present invention, and are quite detailed. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for preparing a cyclohexadienone compound, characterized in that, Using the vinylamide derivative shown in Formula I as a starting material, the reaction is carried out in an organic solvent at a temperature of 10-110 °C under the combined action of phenyldimethylsilane as a hydrogen source, oxidant, and cobalt salt. After the reaction is completed, post-treatment yields the cyclohexadienone compound shown in Formula II. The general reaction formula is as follows: ； In the formula: R 1 It is one of C1-C4 alkyl, C1-C4 alkoxy, phenyl, or phenyl-substituted C1-C4 alkyl; R 2 It is one of C1-C4 alkyl, substituted or unsubstituted phenyl, halogen or thiophene, wherein the substituent on the benzene ring of the substituted phenyl is C1-C4 alkyl, C1-C4 alkoxy, halogen, cyano, trifluoromethyl or trifluoromethoxy.

2. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that, The organic solvent is selected from dichloromethane, dichloroethane, toluene, m-xylene, methanol, ethanol, dimethyl sulfoxide, etc. N , N The organic solvent is selected from any one of dimethylformamide, tetrahydrofuran, acetonitrile, or 1,4-dioxane, and the volume ratio of the organic solvent to the molar ratio of the vinylamide derivative is 5 to 30:1, with volume in milliliters and molar in millimoles.

3. The method for preparing the cyclohexadienone compound according to claim 2, characterized in that, The volume ratio of the organic solvent to the molar ratio of the vinylamide derivative is 8-15:1, with volume measured in milliliters and molars in millimoles.

4. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that, The cobalt catalyst is selected from any one of [cobalt]-1, [cobalt]-2, and [cobalt]-3, and their structures are as follows: ； The molar ratio of the vinylamide derivative to the cobalt catalyst is 1:0.1~0.5, preferably 1:0.1~0.

2.

5. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that, The oxidizing agent is selected from tert-butyl peroxybenzoate, N -Any of fluorobisbenzenesulfonamide, potassium peroxymonosulfonate, and [oxygen]-1, wherein the structure of [oxygen]-1 is as follows: ； The molar ratio of vinylamide derivative to oxidant is 1:1.5-3.

6. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that, The hydrogen source is selected from any one of phenyldimethylsilane, phenylmethylsilane, phenylsilane, and 1,1,3,3-tetramethyldisiloxane, and the molar ratio of the vinylamide derivative to the hydrogen source is 1:1.5-3.

7. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that... The reaction temperature is 20-40℃, preferably 30±2℃, and the reaction time is 6-15 h, preferably 8-12 h.

8. The method for preparing the cyclohexadienone compound according to claim 1, characterized in that, The post-processing steps are as follows: After the reaction is completed, the solvent is removed by rotary evaporation and the target product is obtained by column chromatography; the mobile phase of column chromatography is a mixture of petroleum ether and ethyl acetate with a volume ratio of 1~10:1.

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