Asymmetric Mannich Reaction of Malonates with Aldimines Using Yb III ‐Pybox Complexes Supported on Self‐Assembled Organic–Inorganic Hybrid Silica with an Imidazolium Framework

Yb(OTf) 3 / i Pr‐pybox ( 3b ) immobilized on a self‐assembled organic–inorganic hybrid silica with ionic liquid phase (SAILP) (Catalyst A ) behaves as an efficient and recyclable catalyst in the enantioselective Mannich reaction of malonate esters with N ‐Boc aldimines to afford the corresponding products in good yields and enantioselectivities. In particular, it has been shown that the use of catalyst A resulted in much superior enantioselectivities in comparison with either 1:2 Yb(OTf) 3 / 3b on a periodic mesoporous organosilica with 10 percent imidazolium framework (catalyst C ) or a catalyst comprising 1:1 Yb(OTf) 3 / 3b on SAILP under the same reaction conditions. Catalyst A could be recycled and reused at least four times with only a slight decrease in either catalytic activity or enantioselectivity.