Ru(arene)(amino alcohol)-catalyzed transfer hydrogenation of ketones: mechanism and origin of enantioselectivity

Hybrid density functional methods were used to study the mechanism of the Ru(arene)(amino alcohol)-catalyzed transfer hydrogenation of ketones using isopropyl alcohol as the hydrogen source. An evaluation of three mechanistic alternatives revealed that the reaction took place by means of a six-membered transition state, where a metal-bound hydride and a proton of a coordinated amine were transferred simultaneously to the ketone. Computational results were supported by experimental studies of both rate and enantioselectivity.