Enantioselective Hydrogenation of Aromatic Ketones Catalyzed by a Mesoporous Silica‐Supported Iridium Catalyst

Abstract

Abstract A mesoporous, silica‐supported, chiral iridium catalyst with a highly ordered dimensional‐hexagonal mesostructure was prepared by postgrafting the organometallic complex (1‐diphenylphosphino‐2‐triethylsilylethane)[( R,R )‐1,2‐diphenylethylenediamine]iridium chloride {IrCl[PPh 2 (CH 2 ) 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, silica‐supported, 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.