Organo/metal combined catalysis integrates the catalytic activity of the organocatalyst and metal complex to enable the creation of unprecedented protocols by simultaneous or sequential activation of chemical bonds. On the basis of the activation modes and catalytic pathways, the combined catalysis could be divided into cooperative catalysis, relay catalysis and sequential catalysis. In recent years, the metal/organo combined catalysis has received a great deal of attention, leading to many unprecedented protocols thanks to increasingly deep insight into the concepts of organocatalysis and transition-metal catalysis. Palladium complexes have been one of the most important types of transition metal catalysts and have widely been applied to the organic synthesis. This review will be focused on highlighting recent progress in asymmetric combined catalysis of chiral organocatalysts and palladium complexes, including chiral amines, Brønsted acids, and nucleophilic Lewis bases combined with palladium complexes for the creation of unprecedented transformations. The key issues that need to be addressed in this field are discussed and the perspective of the emerging area are also described.
Contents
1 Introduction
2 Chiral amine/palladium combined catalysis
3 Chiral Brønsted acid/palladium combined catalysis
4 Chiral nucleophilic Lewis base/palladium combined catalysis
5 Conclusion