Synthesis of the side chain of a novel carbapenem via iodine-mediated oxidative cyclization of (1R)-N-(1-aryl-3-butenyl)acetamide.

A (2R,4S)-trans-disubstituted pyrrolidine ring system was constructed by employing iodine-mediated oxidative cyclization of (1R)-N-[1-(4-bromophenyl)-3-butenyl]acetamide 3 as a key step. The resulting diastereomeric mixture of (2R)-2-aryl-4-acetoxypyrrolidine 4 was stereoselectively converted to the side-chain of a novel ultrabroad-spectrum carbapenem 1, via (2R,4R)-2-aryl-4-hydroxypyrrolidine 7.