Diarylprolinol silyl ether salts as new, efficient, water-soluble, and recyclable organocatalysts for the asymmetric Michael addition on water.

A novel strategy for the catalytic asymmetric Michael addition of aldehydes to nitroolefins on water has been developed and provided the Michael adducts in excellent diastereo- and enantioselectivities. A notable feature of these organocatalysts is that they can be recycled for more than six times without a significant loss of catalytic activity and stereochemical control. In addition, the synthetic procedure presented is simple, practical, and environmentally benign.