Vinyl-beta-lactams as efficient synthons. Eco-friendly approaches via microwave assisted reactions

Vinyl-beta-lactams are efficient synthons for a variety of compounds of bio medical interest-such as isocephalosporins, carbapenem and thienamycin inte rmediates, and pyrrolidine alkaloids. Convenient methods are described for obtaining both enantiomers of some of these synthons. Microwave-induced Org anic Reaction Enhancement (MORE) chemistry techniques allow highly accelera ted synthesis of variously substituted vinyl-beta-lactams using limited amo unts of solvents and with efficient stereocontrol-thus achieving high 'atom economy'. The effect (if any) of microwaves on bond angles and bond length s and the geometry of transition stares are not well understood yet. Noneth eless, reactions under microwave irradiation in open systems are rapid, saf e, and cost-effective for synthetic approaches that are much more friendly to the environment than conventional processes. (C) 2000 Elsevier Science L td. All rights reserved.