Aerobic copper-catalyzed homo-coupling of azaallyl anions: A facile access to vicinal diamines

Agitating a mixture of N-(diphenylmethyl)arylaldimine,(BuOK)-Bu-t and catalytic CuCl2 in THF under O-2 atmosphere at 75 degrees C for several hours produces corresponding vicinal diimine. This transformation takes place via a copper-catalyzed oxidative homo-coupling of the in situ generated azaallyl anion, in which molecular oxygen serves as the effective terminal oxidant. 1,2-diarylethane-1,2-diamine dihydrochloride is obtained upon hydrolysis with hydrochloric acid. (C) 2022 Elsevier Ltd. All rights reserved.