作者:Nicolas Duguet、Craig D. Campbell、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/b800857b
日期:——
N-Heterocyclic carbenes promote the formal [2+2] cycloaddition of ketenes with N-tosyl imines to give the corresponding β-lactams in good to excellent isolated yields; chiral NHCs give β-lactams in high e.e. after crystallisation.
fact, their catalytic activity matched those recorded with the free carbenes. Altogether, these results provide strong experimental insight into the mechanism of the Staudinger reaction catalyzed by N‐heterocycliccarbenes. They also highlight the superior catalytic activity of the imidazole‐basedcarbene IMes compared with its saturated analogue SIMes in the reaction under consideration.