A Stereoselective Cyclization Strategy for the Preparation of γ?Lactams and Their Use in the Synthesis of α?Methyl-β-Proline

摘要

A straightforward stereoselective and enantiodivergentncyclization strategy for the construction of γ-lactamsnis described. The cyclization strategy makes use of chiralnmalonic esters prepared from enantiomerically enrichednmonoesters of disubstituted malonic acid. The cyclizationnoccurs with the selective displacement of a substituted benzylnalcohol as the leaving group. A Hammett study illustrates thatnthe cyclization is under electronic control. The resulting γ-nlactam can be readily converted into a novel proline analogue.