Highly Diastereoselective Constructionof Substituted Pyrrolidines: Formal Synthesis of (-)-Bulgecinine

A highly diastereoselective synthesis of substituted pyrrolidines has been achieved starting from nonchiral molecule, allyl bromide, or cis-but-2-ene-1,4-diol. The method involves the asymmetric epoxidation and endo-mode epoxide opening with azide nucleophile as the key steps. The method has been applied for the formal synthesis of (―)-bulgecinine.