Imidazole → (2S,4R)-1-tert-Butyl 2-methyl 4-((tert-butyldimethylsilyl)oxy)pyrrolidine-1,2-dicarboxylate

Participants

Reaction Steps

To a solution of (2S,4R)-1-t-butoxycarbonyl-4-hydroxy-2-methoxycarbonylpyrrolidine (20.0 g) and t-butyldimethylsilyl chloride (18.44 g) in dimethylformamide (60 ml) was added imidazole (11.1 g) under ice-cooling, and the mixture was stirred at 0°-10° C. for 1 hour and then at ambient temperature for 18 hours. The reaction mixture was poured into water (300 ml) and extracted with ethyl acetate (100 ml×3). The combined organic layer was washed with water (200 ml×2) and brine (150 ml) successively, dried over magnesium sulfate, and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (250 g) to give (2S,4R)-1-t-butoxycarbonyl-4-t-butyldimethylsilyloxy-2-methoxycarbonylpyrrolidine (27.95 g).

Provenance & Evidence