Ionically-tagged Transition Metal Catalysts

Modifying catalysts with ionic tags has evolved be to a useful strategy for catalyst immobilization into the liquid phase. Ionic tags enable catalyst recycling, particularly in connection with appropriate reaction media, which are usually ionic liquids or mixtures of ionic liquids and organic solvents or water. Ionic tags are often more than simple anchors. In addition to catalyst recoverability, catalytic activities and stabilities of catalysts are often altered; however, this is difficult to predict at present. This chapter gives an overview of enantioselective ionically-tagged catalysts and their application in asymmetric catalysis. Catalytic activities, recycling and comparison with unmodified catalysts are discussed.