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

Participants

Reaction Steps

To a solution of (2S,4R)-2-(carboxymethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.4 g) in tetrahydrofuran (50 ml) was added triethyamine (1.6 ml). Isobutyl chloroformate (1.1 ml) was dropwise added to the mixture at -5° to -10° C. under nitrogen, followed by stirring for 30 minutes at the same temperature. The insoluble material was filtered off and the filtrate was added to a solution of sodium borohydride (0.70 g) in water (20 ml) at 0° C. After stirring for 2 hours at the same temperature, acetic acid (3 ml) was added thereto. The reaction mixture was evaporated, diluted with ethyl acetate and washed successively with water, saturated sodium bicarbonate and brine. The dried organic layer was concentrated under reduced pressure, and the obtained syrup was subjected to a column chromatography on silica gel and eluted with a mixture of dichloromethane and acetone (4:1 v/v) to give (2S,4R)-2-(2-hydroxyethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.1 g).

Provenance & Evidence