76155-78-7 Biphasic glycerol/2-MeTHF, ruthenium-catalysed enantioselective transfer hydrogenation of ketones using sodium hypophosphite as hydrogen donor

Sodium 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). Sodium hypophosphite has been used in the reduction of ketones in water (nine examples, 40-95 % yield). An original glycerol/2-MeTHF biphasic solvent system has been developed for the enantioselective version of the reaction. This system allows the preparation of aryl alkyl alcohols with up to 97 % ee (22 examples). Copyright https://www.lookchem.com/CASDataBase_76155-78-7.htm

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