Asymmetric Mannich-type reaction catalyzed by palladium complexes

Carbon-carbon bond-forming reactions that involve the addition of resonance -stabilized nucleophiles, such as enols and enolates, to iminium salts and imines, the so-called Mannich-type reactions, comprise one of the most impo rtant classes of reaction in organic synthesis. A number of methods for the diastereoselective reaction of imines with enolates of carboxylic acid der ivatives or silyl ketene acetals have been reported, but examples of enanti oselective variants of this type of reaction are quite limited. This articl e briefly reviews recent progress of enantioselective Mannich-type reaction s, and describes our studies on the enantioselective addition of enol silyl ethers to imines catalyzed by optically active palladium complexes includi ng its mechanistic aspects.