Copper-Catalyzed Consecutive Ullmann, Decarboxylation, Oxidation, and Dehydration Reaction for Synthesis of Pyrrolo or Pyrido[1,2- a ]imidazo[1,2- c ]quinazolines.

A protocol for a copper-catalyzed intermolecular cross-coupling cascade between 2-(2-bromoaryl)-1 H -benzo[ d ]imidazole analogues and proline or pipecolic acid has been developed. The developed protocol allows access to a variety of synthetically useful N -fused pyrrolo or pyrido[1,2- a ]imidazo[1,2- c ]quinazoline scaffolds with high efficiency and good functional group compatibility. Proline or pipecolic acid plays a dual role in the reaction: as ligand and reactants. A mechanistically consecutive approach for the Ullmann coupling, decarboxylation, oxidation, and dehydration reaction process was presented.