Recent Progress in Asymmetric Relay Catalysis of Metal Complex with Chiral Phosphoric Acid

Asymmetric metal/organo relay catalysis, utilizing a metal complex and a chiral organocatalyst in a one-pot cascade reaction, is aimed to sequentially impart activation on multiple steps by distinct catalysts. Such a catalysis merges the advantages of both metal catalysis and organocatalysis, providing step-economy, and, more importantly, the potential to achieve inaccessible reactivity by a single catalyst. Chiral phosphoric acids are among the most robust organocatalysts, rendering a broad range of enantioselective bond-forming reactions. The combination of metal complexes and chiral phosphoric acids in a single vessel has been well documented. In particular, the asymmetric relay catalysis of metal complex with chiral phosphoric acid has grown rapidly since 2008. Several excellent reviews have been published to cover almost all examples in this area from 2008 to early 2014; therefore, in this chapter, we will mainly highlight progress from 2014 to mid-2019.