Mesoporous silica-supported iridium catalysts for asymmetric hydrogenation reactions

Two heterogeneous chiral N-sulfonylated diamine-based eta(5)-Cp*-Ir catalysts with highly ordered dimensional-hexagonal mesostructures were prepared through complexation of [Cp*IrCl(2)](2) with mesoporous SBA-15 type materials containing chiral (S,S)-TsDPEN groups (DPEN 1,2-diphenylethylenediamine). During asymmetric hydrogenation of various aromatic ketones under 10 atm H(2), the end-capping mesoporous catalyst exhibited high catalytic activity and enantioselectivity (up to 93% ee). Such a catalyst could be recovered easily and used repetitively seven times without significantly affecting its catalytic activity and enantioselectivity.