Generation, electrocyclic ring opening, and unprecedented conversion of a 3-acylaminoazetinone into cis-3,4-disubstituted azetidinones

Citation
S. Wolfe et al., Generation, electrocyclic ring opening, and unprecedented conversion of a 3-acylaminoazetinone into cis-3,4-disubstituted azetidinones, CAN J CHEM, 79(8), 2001, pp. 1259-1271
Citations number
83
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE
ISSN journal
0008-4042 → ACNP
Volume
79
Issue
8
Year of publication
2001
Pages
1259 - 1271
Database
ISI
SICI code
0008-4042(200108)79:8<1259:GEROAU>2.0.ZU;2-F
Abstract
An attempt to synthesize the nucleus of cefaclor by insertion of an appropr iately functionalized rhodium carbene into a beta -lactam N-H bond leads in stead to attack at sulfur, followed by fragmentation into a four-membered t hietanone and a four-membered 3-acylaminoazetinone. The azetinone undergoes electrocyclic ring opening, with a calculated half-life of 11 s at 40 degr eesC, to a trans-disubstituted vinyl isocyanate, but can be trapped by satu rated, unsaturated allylic and benzylic alcohols to form 3,4-disubstituted azetidinones in which the cis- isomer predominates.