Ligand-free Cu2O-catalyzed cross coupling of nitrogen heterocycles with iodopyridines

A practical and efficient strategy has been developed for the cross coupling of nitrogen heterocycles with halopyridines using ligand-free Cu2O as catalyst and Cs2CO3 as the base. The protocol is applicable to a series of highly functionalised heterocycles, such as 7-azaindole, indazole, indole, imidazole, pyrrole and pyrazole, affording the N-heteroaryl derivatives in high yields (up to 96%).