On the effect of ring substituents in the carbonylation of aziridines

The effect of ring substituents on the cobalt carbonyl-catalyzed carbonylation of functionalized aziridines to beta -lactams has been investigated. A variety of aziridines with different substituents and stereochemistry has been synthesized and subjected to carbonylation. The ring expansion to beta -lactam takes place in the absence of an electron-withdrawing substituent and higher yields are always obtained for cis-aziridines. Moreover, the regioselectivity of the reaction is affected by the nature of substituents at ring carbon atoms. (C) 2001 Elsevier Science Ltd. All rights reserved.