Under ice-cooling, to 10 ml of an anhydrous tetrahydrofuran solution containing 299 mg (1.84 mmol) of (2S-trans)-3-butyl-oxiranecarboxylic acid.dicyclohexylammonium salt was added 2 ml of an anhydrous tetrahydrofuran solution containing 222 mg (1.84 mmol) of pivaloyl chloride, and the resulting mixture was stirred at the same temperature for 15 minutes. Moreover, the temperature of the reaction mixture was returned to room temperature, and the mixture was stirred for 2 hours. After insoluble material in the reaction mixture was filtred off, the filtrate was added to 10 ml of an anhydrous tetrahydrofuran solution containing 252 mg (1.84 mmol) of 3,4-methylenedioxyaniline under ice-cooling, and the resulting mixture was stirred at room temperature for 2 hours. Under reduced pressure, the reaction mixture was concentrated, ethyl acetate was added to the concentrate, and the resulting mixture was washed successively with a 10% aqueous potassium hydrogen sulfate solution, a saturated aqueous sodium hydrogen carbonate solution and then a saturated NaCl solution. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to obtain 484 mg (Yield: 100%) of the title compound.
