Highly enantioselective Michael addition reactions in water catalyzed by an insoluble MPS-supported 4-sulfonamidyl prolinol tert-butyldiphenylsilyl ether

The development of a highly efficient, insoluble, and non-swelling MPS-supported organocatalyst for the direct asymmetric Michael reaction of ketones and aldehydes to nitrostyrenes at room temperature in water is described. Excellent yields (up to 100%) and high stereoselectivities (up to 94% dr and 93% ee) were achieved with 10 mol % of the catalyst. The resin-bound catalyst was simply separated and recovered by filtration, and reused for six consecutive trials without significant loss of activity and enantioselectivity.