Supported ionic liquid asymmetric cathalysis. A new method for chiral catalyst recycling

A new method for chiral catalysts recycling, based on the supported ionic liquid asymmetric catalysis concept, has beendeveloped. This concept involves the treatment of a monolayer of covalently attached ionic liquid on the surface of silica gel withadditional ionic liquid. These layers serve as the reaction phase in which the homogeneous chiral catalyst is dissolved. As firstapplication of this concept the L-proline-catalyzed aldol reaction has been carried out. Good yields and ee values, comparable withthose obtained under homogeneous conditions have been obtained. Moreover, this material shows high regenerability.