Copper-Catalyzed Oxidative C−H Amination: Synthesis of Imidazo[1,2-a]-N-Heterocycles from N-Heteroaryl Enaminones

A copper(I)-catalyzed oxidative C−N bond cross-coupling reactions for the construction of imidazole-containing nitrogen bridgehead heterocycles have been developed under ligand- and base-free conditions. The open-air reaction conditions were general and successfully applied in the synthesis of heterocycles, such as substituted imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[1,2-a]pyrazines.