Chemistry of Ammonium Betaines: Application to Ion-Pair Catalysis for Selective Organic Transformations

抄録

The ammonium betaine was developed as an intramolecular ion-pair catalyst for realizing cooperative catalysis of a cation and anion; i.e. ion-pair catalysis. Combination of the stereocontrolling ability of the chiral ammonium ion and functions of the pairing aryloxylate ion enabled bifunctional organic base catalysis and ionic nucleophilic catalysis, which facilitate a variety of organic transformations with rigorous stereochemical control. In addition, employing a single-electron-accepting cation as a partner of the basic aryloxylate led to the development of a chemical redox catalyst with the capability of proton-coupled electron transfer (PCET). This research demonstrates a power of the ion-pair catalysis in selective organic synthesis and is therefore likely to stimulate further study in this field.