Biphasic Glycerol/2‐MeTHF, Ruthenium‐Catalysed Enantioselective Transfer Hydrogenation of Ketones Using Sodium Hypophosphite as Hydrogen Donor

Abstract

AbstractSodium hypophosphite has been used as an efficient hydrogen donor in the transfer hydrogenation of aliphatic and aromatic ketones in the presence of [RuCl2(p‐cymene)]2 and 2,2′‐bipyridine in water. The corresponding alcohols were isolated in moderate to excellent yields (39–95 %). Good chemoselectivity was observed with ester, nitrile and halide functionalities in the ketones not being reduced. An enantioselective version of the reaction using [RuCl(p‐cymene){(R,R)‐TsDPEN}] as catalyst in a glycerol/2‐MeTHF biphasic solvent mixture has been developed and allowed the reduction of (hetero)aromatic ketones with excellent chemo‐ and enantioselectivities (up to 97 % ee).