Copper-Mediated 1,4-Diamination of 1,3-Butadienes

A copper(II)-mediated diamination of 1,3-butadienes is reported. The reaction employs an inorganic base, copper dibromide as a reagent, and saccharin as the nitrogen source. The diamination proceeds for a series of 1,3-butadienes under relatively mild conditions with complete selectivity in favor of the 1,4-oxidation products.