Copper-catalyzed Mannich-type oxidative β-functionalization of tertiary amines.

A copper-catalyzed Mannich-type oxidative β-functionalization reaction of amines has been developed. In the presence of an oxidant and a copper catalyst, tertiary amines reacted with N-tosylimines, providing synthetically important 1,3-diamines and enamines, respectively. Preliminary mechanistic studies suggested that the oxidation of the tertiary amine to the enamine intermediate triggers subsequent Mannich-type reactions with N-tosylimines and thus enables the direct β-functionalization of the tertiary amines.