Acidic Hydrogen-Tethered Electron-Deficient Acceptors for Phosphine-Catalyzed Annulations

Nucleophilic phosphine-catalyzed annulations are recognized as practical and powerful synthetic tools for various cyclic compounds. Phosphine acceptors play a key role in nucleophilic phosphine catalysis. Design and synthesis of new phosphine acceptors, which are able to introduce new zwitterionic intermediates with new reactivities into the phosphine-catalyzed annulations, are highly desirable. Recently, we applied the proton shift principles in the design of new phosphine acceptors and have developed several phosphine-catalyzed annulation reactions with the use of new phosphine acceptors. In this account, we present a brief introduction of design and application of a series of acidic hydrogen-tethered electron-deficient acceptors for phosphine-catalyzed annulation reactions, categorizing with the atom types (N-H, O-H, C-H) that acidic hydrogen is bounded to.