Diethyl (2-amino-2-oxoethyl)phosphonate → (2R,4R)-1-allyloxycarbonyl-4-tert-butyl-dimethylsilyloxy-2-[2-{4-(2-carbamoylethenyl)imidazol-1-yl}ethyl]pyrrolidine

Participants

Reaction Steps

To a solution of diethyl carbamoylmethylphosphonate (12.7 g) and potassium tert-butoxide (13.9 g) in tetrahydrofuran (400 ml) were added a solution of (2R,4R)-1-allyloxycarbonyl-4-tert-butyldimethylsilyloxy-2-{2-(4-formylimidazol-1-yl)ethyl}pyrrolidine (24 g) in tetrahydrofuran (50 ml) at 45° C. After stirring for 1 hour, to the reaction mixture were added water (3 ml). Evaporation of the solvent gave a residue, which was dissolved in a mixture of ethyl acetate (500 ml) and water (50 ml). The organic layer was separated, washed in turn with water (50 ml×2) and brine (50 ml×2), and dried over magnesium sulfate. Evaporation of the solvent gave an oil, which was chromatographed on silica gel (500 ml) eluting with a mixture of dichloromethane and methanol (10:1) to give (2R,4R)-1-allyloxycarbonyl-4-tert-butyl-dimethylsilyloxy-2-[2-{4-(2-carbamoylethenyl)imidazol-1-yl}ethyl]pyrrolidine (13.87 g).

Provenance & Evidence