68 mg (70% by weight, 0.28 mmol) of meta-chloroperbenzoic acid were added to 100 mg (0.28 mmol) of 3-(2-methoxy-3-methylthio-4-(trifluoromethyl)benzoyloxy)-cyclohex-2-enone in 10 ml of dichloromethane. The mixture was stirred at RT for 1 h. For work-up, 3 ml of 10 percent strength aqueous sodium hydrogensulfite solution were added. After confirmation that no peroxides were present, the organic phase was washed twice with in each case 5 ml of saturated aqueous NaHCO3 solution. After phase separation, the solvent was removed. This gave 90 mg of 3-(2-methoxy-3-methylsulfinyl-4-(trifluoromethyl)benzoyloxy)cyclohex-2-enone.
