Enantioselective organocatalytic Michael addition of malonates to α,β-unsaturated aldehydes in water

The Michael addition of malonates to alpha,beta-unsaturated aldehydes catalyzed by O-TMS protected diphenylprolinols and acetic acid in water occurs at 0 degrees C to rt. In most cases, the reaction runs to completion in less than 24 h. A wide range of aldehydes including beta-aryl, beta-alkyl and beta-alkenyl acroleins are found to be compatible with these conditions, providing the corresponding adducts in good yields and with good to excellent enantioselectivities. (C) 2008 Elsevier Ltd. All rights reserved.