Enantioselective hydrogenation of aromatic ketones catalyzed by a mesoporous silica-supported iridium catalyst

A mesoporous, silica-supported, chiral iridium catalyst with a highly ordered dimensionalhexagonal mesostructure was prepared by postgrafting the organometallic complex (1-diphenylphosphino-2-triethylsilylethane)[(R,R)-1,2-diphenylethyle- nediamine]iridium chloride {IrCl[PPh2(CH2)(2)Si(OEt)(3)](2)[(R,R)-DPEN] (DPEN = 1,2-diphenylethylenediamine)} on SBA-15 silica. During the asymmetric hydrogenation of various aromatic ketones under 40 atm of hydrogen, the mesoporous, silicasupported, chiral iridium catalyst exhibited high catalytic activity (more than 95% conversions) and excellent enantioselectivity (up to more than 99% ee). The catalyst could be recovered easily and used repetitively seven times without significantly affecting the catalytic activity and the enantioselectivity.