SYNTHESIS OF BETA-LACTAMS BY CONDENSATION OF TITANIUM ENOLATES OF 2-PYRIDYLTHIOESTERS WITH IMINES - INFLUENCE OF THE IMINE STRUCTURE ON THE TRANS/CIS STEREOSELECTIVITY

被引:23
作者
ANNUNZIATA, R [1 ]
BENAGLIA, M [1 ]
CINQUINI, M [1 ]
COZZI, F [1 ]
PONZINI, F [1 ]
RAIMONDI, L [1 ]
机构
[1] UNIV MILAN,DIPARTIMENTO CHIM ORGAN & IND,I-20133 MILAN,ITALY
关键词
D O I
10.1016/S0040-4020(01)87005-8
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
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.
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页码:2939 / 2948
页数:10
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