Water → (2S,4R)-4-Hydroxypyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

Participants

Reaction Steps

To a solution of (2S,4R)-1-(tert-butoxycarbonyl)-2-carboxy-4-hydroxypyrrolidine (103 g) and potassium carbonate (64.6 g) in dimethylformamide (500 ml) was added methyl iodide (33.2 ml) at 0° C., and the mixture was stirred for three hours. The reaction mixture was poured into a mixture of water (1 l) and ethyl acetate (1 l), and the organic layer was separated, washed in turn with water (500 ml) and brine, and dried over magnesium sulfate. Evaporation of the solvent gave an oil, which was chromatographed on silica gel (800 ml) eluting with a mixture of hexane and ethyl acetate (1:2, V/V) to give (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxy-2-methoxycarbonylpyrrolidine (105.2 g).

Provenance & Evidence