The general procedure for the synthesis of 4-acetyl-1-methyl-cyclohexene from the compound (CAS: 55511-67-6) was as follows: a crude mixture of 12 and 9 (1.48 g) was dissolved in dichloromethane (8 mL) at 0°C and added slowly and dropwise to a pre-prepared dichloromethane (2.69 g, 7.77 mmol) and diatomaceous earth (2.67 g) (40 mL) suspension. After dropwise addition, the reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, it was filtered through a short diatomaceous earth pad and silica gel column and rinsed with dichloromethane. After evaporation to remove the solvent, the crude product was further purified by silica gel column chromatography using petroleum ether/ethyl ether (8:2) as eluent, resulting in 410 mg of 9 as a light yellow oil. When purified 12 (543 mg, 3.9 mmol) was used as starting material, the same experimental protocol was employed to obtain 500 mg (93% yield) of the target product. The structure of the product was confirmed by the following characterization data: 1H NMR (400 MHz, CDCl3): δ5.31 (s, 1H), 2.50-2.39 (m, 1H), 2.16-1.84 (m, 6H), 2.10 (s, 3H), 1.58 (s, 3H). 13C NMR (100 MHz, CDCl3): δ211.99 ,133.77, 119.23, 47.20, 29.46, 27.92, 27.02, 24.87, 23.36. MS (EI, 70eV, m/z %): 43 (32), 67 (36), 77 (17), 79 (26), 93 (18), 95 (78), 105 (17), 123 (50), 138 ( M+, 100).
