One-pot synthesis of unsymmetrical benzils and N-heteroarenes through nucleophilic aroylation catalyzed by N-heterocyclic carbene

An efficient one-pot synthesis of various unsymmetrical benzils via N-heterocyclic carbene (NHC)-catalyzed aroylation of N-phenylimidoyl chlorides with aromatic aldehydes followed by acidic hydrolysis has been developed. The one-pot procedure was extended to synthesis of quinoxalines and pyrazines by condensation/annulation of unsymmetrical benzils generated in situ with diamines.