Asymmetric Mannich-type reaction catalyzed by palladium complexes

Abstract

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 important classes of reaction in organic synthesis. A number of methods for the diastereoselective reaction of imines with enolates of carboxylic acid derivatives or silyl ketene acetals have been reported, but examples of enantioselective variants of this type of reaction are quite limited. This article briefly reviews recent progress of enantioselective Mannich-type reactions, and describes our studies on the enantioselective addition of enol silyl ethers to imines catalyzed by optically active palladium complexes including its mechanistic aspects.