title: A Novel One-Step Diastereo- and Enantioselective Formation of trans-Azetidinones and Its Application to the Total Synthesis of Cholesterol Absorption Inhibitors.
abstract: An efficient and practical asymmetric process was developed for the synthesis of azetidinone-based cholesterol absorption inhibitors. Key to this synthesis was the discovery of a novel one-step diastereo- and enantioselective formation of trans beta-lactams starting from commercially available 3(S)-hydroxy-gamma-lactone. Various trans beta-lactams can be prepared in good yields and with better than 95:5 enantio- and diastereoselctivity. A Lewis acid-catalyzed aldol condensation and a highly enantioselective oxazaborolidine-catalyzed chiral reduction completes the side chain.
authors.affiliation: Chemical Process Research and Development, Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, New Jersey 07033.
authors.forename: Guangzhong
authors.initials: G
authors.lastname: Wu
authors.forename: YeeShing
authors.initials: Y
authors.lastname: Wong
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Ding