Asymmetric Cross- and Self-Aldol Reactions of Aldehydes in Water with a Polystyrene-Supported Triazolylproline Organocatalyst.

A polystyrene (PS) immobilized triazolylproline has been prepared by a bottom-up approach involving co-polymerization with full regiocontrol. The resulting PS resin swells in water and has been applied to the enantioselective cross-aldol reaction and to the self-aldol reaction of aldehydes under essentially neat conditions, excellent yields and stereoselectivities being recorded.