The enantiomerically pure crystalline α,β-unsaturated γ-lactams 4 and 5 have been synthesized by utilizing 2,3-O-isopropylidene-D-glyceraldehyde (3) as chiral source and novel N-tert-butoxycarbonyl-2-(tert-butyldimethylsiloxy)pyrrole (TBSOP) as four carbon homologative reagent. Unsaturated lactam 4 has been selectively elaborated into hydroxylated pyrrolidinones 7, 8, and 11 by stereocontrolled procedures involving conjugate addition of organocuprates, cis-dihydroxylation, and α-alkylation via hydrogenation and enulate formation. The absolute stereochemistries of 4 and 5 have been secured by single crystal X-ray analyses. © 1992.
Homochiral α,β-unsaturated γ-lactams: Versatile templates / Rassu, Gloria; Casiraghi, Giovanni; Spanu, Pietro; Pinna, Luigi; Fava, Giovanna Gasparri; Ferrari, Marisa Belicchi; Pelosi, Giorgio. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 3:8(1992), pp. 1035-1048. [10.1016/S0957-4166(00)86037-1]
Homochiral α,β-unsaturated γ-lactams: Versatile templates
CASIRAGHI, Giovanni;PELOSI, Giorgio
1992-01-01
Abstract
The enantiomerically pure crystalline α,β-unsaturated γ-lactams 4 and 5 have been synthesized by utilizing 2,3-O-isopropylidene-D-glyceraldehyde (3) as chiral source and novel N-tert-butoxycarbonyl-2-(tert-butyldimethylsiloxy)pyrrole (TBSOP) as four carbon homologative reagent. Unsaturated lactam 4 has been selectively elaborated into hydroxylated pyrrolidinones 7, 8, and 11 by stereocontrolled procedures involving conjugate addition of organocuprates, cis-dihydroxylation, and α-alkylation via hydrogenation and enulate formation. The absolute stereochemistries of 4 and 5 have been secured by single crystal X-ray analyses. © 1992.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
