ABSTRACT
The notable use of phosphorus-containing organic Brønsted acids in catalysis dated back to the 1970s, when Sir John Cornforth designed a series of phosphinic acids with rigid backbones to mimic the elegant mechanics of Nature in synthesis of small molecules. When Akiyama and Terada reported the application of phosphoric acid with chiral backbone to catalyze asymmetric Mannich reaction in 2004, the field of chiral phosphoric acid catalysis started to blossom and have since become the primary interest of many research groups. The report has inspired numerous creative affords to synthesize phosphoric acid catalysts with different chiral backbones, steric environment, and acidity, with the goal to further expand the application of chiral phosphoric acids in organic synthesis. In this chapter, the discussion will focus on various modes of participation of phosphorus-based Brønsted acids in catalysis, which include counter ion catalysis, bifunctional hydrogen-bonding activation, cooperative catalysis with Lewis acid, chiral proton source, and covalent phosphate catalysis.
