反应详情

10.8 g (33.4 mmol) of benzyl (4R)-4-t-butoxycarbonylamino-5-hydroxypentanoate and 3.4 g (33.4 mmol) of triethylamine were stirred in 200 ml of dichloromethane. 3.83 g (33.4 mmol) of methanesulfonyl chloride was added to the obtained mixture under cooling with ice. Crude benzyl (4R)-4-t-butoxycarbonylamino-5-methanesulfonyloxypentanoate was obtained by an ordinary method with dichloromethane as the extracting solvent. The crude product was stirred together with 7.2 g (170 mmol) of lithium chloride in 50 ml of DMF at 50° C. overnight. The solvent was evaporated, and the crude title compound obtained by an ordinary method with ethyl acetate as the extracting solvent was washed with a solvent mixture of hexane and ethyl acetate to obtain the title compound.

1. temperatureunder cooling with ice