Aluminium complex as an efficient catalyst for the chemo-selective reduction of amides to amines

Abstract

We report an efficient protocol for the catalytic chemo-selective reduction of tert-amides with pinacolborane (HBpin) to afford the corresponding amines in high yields using aluminium complexes [κ²-{Ph₂P(X)NC₉H₆N}Al(Me)₂] [X = S (2a), Se (2b)] as pre-catalysts at room temperature. The aluminium complexes were prepared from the reaction of [Ph₂P(X)NC₉H₆N] [X = S (1a), Se (1b)] and trimethylaluminium in toluene. The solid-state structure of complex 2b is established. Tertiary amides with a wide array of electron-withdrawing and electron-donating functional groups were easily converted to the desired products through the selective cleavage of the amides’ CO bond by aluminium hydride as an active species. A kinetic study of the catalytic reaction is also reported.