Triphenylphosphine → cis-1-(p-nitrobenzyloxycarbonyl)-4-acetylthio-L-proline p-methoxybenzyl ester

Participants

Reaction Steps

8.6 g of trans-1-(p-nitrobenzyloxycarbonyl)-4-hydroxy-L-proline-p-methoxybenzyl ester and 7.86 g of triphenylphosphine were dissolved in 20 ml of dried tetrahydrofuran. To the resulting solution was added dropwise a solution of 5.22 g of diethyl azodicarboxylate in 5 ml of dried tetrahydrofuran under ice-cooling in a nitrogen stream, followed by stirring for 30 minutes at that temperature. Thereafter, 2.28 g of thioacetic acid was added thereto dropwise, and the mixture was stirred for 1 hour under ice-cooling and then at room temperature for 3 hours, followed by concentration. The residue was purified by silica gel column chromatography to obtain cis-1-(p-nitrobenzyloxycarbonyl)-4-acetylthio-L-proline p-methoxybenzyl ester.

Provenance & Evidence