Asymmetric hydrogenation of aromatic ketones using new chiral-bridged diphosphine/diamine-Ru(II) complexes

摘要

A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new ((Rax)-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, 20atm. of H2, 20°C, 48h) afforded (S)-1-(2′-methylphenyl)ethanol in 92% ee and 99% conversion.