Enhanced activity and stereoselectivity of polystyrene-supported proline-based organic catalysts for direct asymmetric aldol reaction in water

Several polystyrene-supported proline dipeptides and a prolinamide derivative have been prepared via the thiol-ene coupling. These materials have been used as catalysts for the direct asymmetric aldol reaction in water and results compared with unsupported catalysts in water. Such approach gave more active or stereoselective catalysts compared to the unsupported compounds showing that our immobilization procedure may be useful in order to develop more performing catalytic materials. Moreover, these catalysts can be recovered and reused at least up to nine times without loss in acitivity or can be easily regenerated when their activity decreased.