反应详情

A 1.6M solution (4.2 ml) of butyllithium in hexane was added to a solution of (2S,4R)-1-benzyloxycarbonyl-2-hydroxymethyl-4-methanesulfonyloxypyrrolidine (2.00 g) at -30°-20° C. with stirring in a stream of nitrogen and the mixture was stirred at the same temperature for 30 minutes. Ethyl bromoacetate (2.4 ml) was added to the mixture at -30°~-20° C. and the solution was stirred at 10-15° C. for 3 hours. The solution was poured into 0.1N hydrochloric acid (50 ml) extracted with ethyl acetate (50 ml), dried over magnesium sulfate and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (20 g) and eluted with chloroform to give (2S,4R)-1-benzyloxycarbonyl-2-(ethoxycarbonylmethyl)oxymethyl-4-methanesulfonyloxypyrrolidine (1.87 g).

1. stirringthe mixture was stirred at the same temperature for 30 minutes
2. stirringthe solution was stirred at 10-15° C. for 3 hours
3. extractionextracted with ethyl acetate (50 ml)
4. dry with materialdried over magnesium sulfate
5. concentrationconcentrated under reduced pressure
6. customto give a syrup
7. washeluted with chloroform