A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new((R_(ax))-BuP)/(R,R)-DPEN-Ru(Ⅱ) complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol (t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H_2,20℃,48 h) afforded(S)-1-(2'-methylphenyl)ethanol in 92%ee and>99% conversion.
