(3S)-3-mercapto-1-(4-nitrobenzyloxycarbonyl)pyrrolidine → (2S,4R)-4-t-butyldimethylsilyloxy-1-(4-nitrobenzyloxycarbonyl)-2-[{(3S)-1-(4-nitrobenzyloxycarbonyl)pyrrolidin-3-ylthio}methyl]pyrrolidine

Participants

Reaction Steps

To a solution of (3S)-3-mercapto-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (1.36 g) in methanol (5 ml) was added 28% sodium methoxide-methanol solution (0.97 ml) under ice-cooling and the mixture was stirred at the same temperature for 10 minutes. This solution was added to a solution of (2S,4R)-4-t-butyldimethylsilyloxy-2-methanesulfonyloxymethyl-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2 g) in methanol (20 ml). The mixture was stirred at ambient temperature for 3 hours and then at 50°-60° C. for 5 hours. The reaction mixture was evaporated in vacuo to give a residue. The residue was dissolved in ethyl acetate (50 ml). The solution was washed with saturated aqueous sodium chloride, dried over magnesium sulfate and evaporated in vacuo. The resulting residue was chromatographed on silica gel (100 g) eluting with a mixture of n-hexane and ethyl acetate (2:1 v/v). The fractions containing the desired compound were collected and evaporated in vacuo to give (2S,4R)-4-t-butyldimethylsilyloxy-1-(4-nitrobenzyloxycarbonyl)-2 -[{(3S)-1-(4-nitrobenzyloxycarbonyl)pyrrolidin-3-ylthio}methyl]pyrrolidine (1.95 g).

Provenance & Evidence