A novel regioselective metal-catalyzed spirocyclization of alpha-allenols-cross coupling (Heck, Sonogashira, and Suzuki) reaction sequence, leading to potentially bioactive spirocyclic lactam derivatives has been developed. Precursors for the tandem spirocyclization-coupling reaction, alpha-allenols 2 a-d were obtained starting from alpha-oxolactams 1 a-c via indium-mediated Barbier-type carbonyl-allenylation
Diversity-Oriented Preparation of Enantiopure Spirocyclic 2-Azetidinones from α-Oxo-β-lactams through Barbier-Type Reactions followed by Metal-Catalyzed Cyclizations
作者:Benito Alcaide、Pedro Almendros、Teresa Martínez del Campo、Raquel Rodríguez-Acebes
DOI:10.1002/adsc.200600502
日期:2007.3.5
Novel, simple, and convenient strategies to diversely functionalized spirocyclic β-lactams have been developed by using different metal-mediated carbonyl addition/cyclizationreaction sequences. Spirocyclization precursors, 2-azetidinone-tethered homoallylic alcohols, bromohomoallylic alcohols, homopropargylic alcohols, (buta-1,3-dien-2-yl)methanols, and α-allenols have been obtained by regioselective
A novel approach to enantiopure spirocyclic beta-lactams has been developed by using different intramolecular metal-catalyzed cyclization reactions in monocyclic unsaturated alcohols. The access to cyclization precursors, 2-azetidinone-tethered homoallylic alcohols, (buta-1,3-dien2-yl)methanols, and alpha-allenols was achieved by regio and stereoselective addition of stabilized organo-indium reagents to azetidine-2,3-diones in aqueous environment. (C) 2004 Elsevier Ltd. All rights reserved.