Abstract
The enantiospecific synthesis of 3-acetoxy-trans-beta-lactams via the Staudinger [2+2] cycloaddition reaction of polyaromatic imines with bicyclic (+)-car-3-ene was investigated. The sterically hindered polyaromatic substituent at the N(1)position in the imines plays a significant role, directing the cycloaddition reaction to stereoselective formation oftrans-(3R,4R)-N-azetidin-2-ones. The results as described herein are highly unprecedented, since the synthesis of a single optically activetrans-beta-lactam, starting from a chiral ketene, has never been reported previously.