On the Efffect of Ring Substituent in the Carbonylation of Aziridines

The effect of ring substituents on the cobalt carbonyl-catalyzed carbonylation of functionalized aziridines to β-lactams has been investigated. A variety of aziridines with different substituents and stereochemistry has been synthesized and subjected to carbonylation. The ring expansion to β-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