Triethylamine → (2S,4R)-2-(2-hydroxyethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Participants

Reaction Steps

A solution of isobutyl chloroformate (1.08 ml) in tetrahydrofuran (3 ml) was dropwise added to a solution of (2S,4R)-2-(carboxymethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.4 g) and triethylamine (1.55 ml) in tetrahydrofuran (50 ml) at -10°~5° C., and the mixture was stirred at the same temperature for 0.5 hour. The precipitate was filtered off. To the filtrate was added sodium borohydride (0.7 g) and water (30 ml) at 0° C. After 1 hour, glacial acetic acid (3 ml) was added to the mixture. The mixture was poured into a mixture of water (50 ml) and ethyl acetate (50 ml). The organic layer was separated, washed with water, saturated aqueous sodium hydrogen carbonate and brine in turn, dried over magnesium sulfate, and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (30 g) and eluted with a mixture of methanol and chloroform (5:95 V/V) to give (2S,4R)-2-(2-hydroxyethyloxymethyl)-4 -methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.10 g).

Provenance & Evidence