Asymmetric Assisted Catalysis by Multicatalyst System

This chapter focuses on in-depth discussion about some representative achievements of asymmetric assisted catalysis (AAC) mediated by multicatalyst system. To simplify the discussion, a two-catalyst system is used. Typically, neither of the two catalysts is impotent for the reaction by itself, namely no or low reactivity/enantioselectivity; however, the favorable interactions between catalyst I and II contribute to a highly active catalytic species to achieve the desired reactivity and stereoselectivities. The AAC mediated by multicatalysts systems include three major types: (1) assisted catalysis within acids and bases, including all possibilities of the assistance of a Brønsted acid (BA), Lewis acid (LA), Brønsted base (BB), and Lewis base (LB); (2) modulation of a complex with a chiral ligand; and (3) supramolecular-type catalysis, the organization of two or more distinct catalysts via non-covalent interactions to perform catalysis. The chapter discusses the three major types of AAC in detail.