Homochiral alfa-beta-Unsaturated y-Lactams: Versatile Templates

The enantiomerically pure crystalline alfa, beta-unsaturated y-lactams 4 and 5 have been synthesized by utilizing 2,3-0-isopropylidene-D-glyceraldehyde (3) as chiral source and novel N-tertbutoxycarbonyl- 2-(tert-butyldimethylsiloxy)pyrrole( TBSOP) as four carbon homologative reagent. Unsaturated lactam 4 has been selectively elaborated into hydrox)rIated pyrrolidinones 7,8, and 11 by stereocontrolled procedures involving conjugate addition of organocuprates, cis-dihydroxylation, and alfa-alkylation via hydrogenation and enolate formation. The absolute stereochemistries of 4 and 5 have been secured by single crystal X-ray analyses.