Enamine catalysis Michael addition, aldehyde acceptors

The best alternatives to enamines for conjugate addition of aldehyde, ketone, and acid derivative enols are silyl enol ethers, Their formation and some uses were discussed in Chapters 21 and 26-28, but these stable neutral nueleophiles also react very well with Michael acceptors either spontaneously or with Lewis acid catalysis at low temperature,... 

A wide variety of carbon nucleophiles have been successfully used in the organocatalytic asymmetric inter- and intramolecular Michael addition to different a,p-unsaturated systems. Among them, the addition of aldehydes to diverse Michael acceptors such as, a,p-unsaturated ketones, alkylidene malonates, P-nitrostyrenes, and vinyl sulfones, is one of the most studied reactions. Enamine catalysis is the most frequently employed chiral activation found in the literature. 

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