Practical Asymmetric Approach to Pyrrolidinones: Efficient Synthesis of (+)-Preussin and (−)-AHPPA

Abstract

A novel, dichloroketene−chiral enol ether cycloaddition-based synthesis of enantiopure (+)-preussin and (−)-AHPPA has been realized. The efficient, highly stereoselective approach, which involves a Beckmann ring expansion reaction to access the key pyrrolidinone, proceeds in ca. 16% overall yield for each of the compounds.