The condensation of the titanium enolates of C-2 alkyl substituted 2-pyridylthioesters with imines affords beta-lactams in trans/cis ratios that largely depend on the structure of the C-imine residue. Bulky and non-chelating heteroatom-containing groups lead to the formation of trans p-lactams, while sterically non-requiring or chelating groups favour the formation of the cia-products. On the basis of NMR evidences a rationale is proposed to account for the observed stereoselectivity.
SYNTHESIS OF BETA-LACTAMS BY CONDENSATION OF TITANIUM ENOLATES OF 2-PYRIDYLTHIOESTERS WITH IMINES - INFLUENCE OF THE IMINE STRUCTURE ON THE TRANS/CIS STEREOSELECTIVITY / R. ANNUNZIATA, M. BENAGLIA, M. CINQUINI, F. COZZI, F. PONZINI, L. RAIMONDI. - In: TETRAHEDRON. - ISSN 0040-4020. - 50:9(1994), pp. 2939-2948.
Titolo: | SYNTHESIS OF BETA-LACTAMS BY CONDENSATION OF TITANIUM ENOLATES OF 2-PYRIDYLTHIOESTERS WITH IMINES - INFLUENCE OF THE IMINE STRUCTURE ON THE TRANS/CIS STEREOSELECTIVITY | |
Autori: | ANNUNZIATA, RITA MARIA (Primo) BENAGLIA, MAURIZIO (Secondo) RAIMONDI, LAURA MARIA (Ultimo) | |
Settore Scientifico Disciplinare: | Settore CHIM/06 - Chimica Organica | |
Data di pubblicazione: | 1994 | |
Rivista: | ||
Tipologia: | Article (author) | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1016/S0040-4020(01)87005-8 | |
Appare nelle tipologie: | 01 - Articolo su periodico |