Oxidative N-heterocyclic carbene (NHC) catalysis for the rapid access to functionalized pyrrolo-oxazinones

Abstract

The N-heterocyclic carbene (NHC)-catalyzed intramolecular cyclization of N-substituted pyrrole 2-carboxaldehydes under oxidative conditions allowing the facile synthesis of pyrrolo-oxazinone derivatives is reported. The keys to the success of this strategy are the generation of acylazoliums using NHC and the base-mediated formation of the enolate. Subsequent intramolecular acylation of the enolate with the acylazoliums afforded the desired product. Mild reaction conditions, good functional group compatibility and high yields of products are the advantages of the present annulation.