Pd(0)-catalyzed atom transfer radical cyclization of N-allyl-α-chloroamides: highly stereoselective synthesis of substituted γ-lactam

Abstract

A catalysis system comprised of Pd(cod)Cl2 precursor and IMes ligand has been developed, which is efficient to catalyze the atom transfer radical cyclization of N-allyl-α-chloroamides with the help of NaI additive. This reaction provides a facile access to β-iodomethyl-γ-lactam with high stereoselectivity. Moreover, the results from the reaction of deuterium-labeled substrate and TEMPO-trapping experiment clearly indicate that radical intermediate(s) should be involved in the reaction.