Catalysts for the asymmetric transfer hydrogenation of ketones derived from L-prolinamide and (p-cymeneRuCl2)2 or (Cp*RhCl2)2

The combination of L-prolinamide with (p-CymeneRuCl(2))(2) or (Cp*RhCl2)(2) in the presence of KOH/2-propanol, has been found to generate catalysts in situ that are capable of enantioselectively reducing aryl ketones to the respective (R)-alcohols. Furthermore, when the catalyst derived from (p-CymeneRuCl(2))(2)/L-prolinamide was applied to the asymmetric reduction of 1'-tetralone at -24 degreesC, (R)-tetralol was produced in 93% ee.