2,2,2-Trifluoroethanol-assisted imine hydrogenation by a Ru-monohydride

The trans heterodiphosphane Ru-based compound of the formula [Ru(OAc)2(CO)2(PnBu3)(PPh3)] proved to be a suitable precatalyst for imine hydrogenation in 2,2,2-trifluoroethanol (TFE) without the addition of an external base. High-pressure (HP) NMR investigations combined with a DFT-study, carried out on a related model precatalyst, were indicating the formation of a cationic Ru-monohydride-2,2,2-trifluoroethanol (TFE) species that catalyzes the imine hydrogenation by a TFE-assisted outer-sphere reaction mechanism.