Quaternary phosphonium salts in the synthetic chemistry: Recent progress, development, and future perspectives

Progress a chemical reaction through catalysis is a privileged approach that includes almost 95% (in volume) of all of the usual chemical compounds. Therefore investigation about high efficient catalysts is an attractive and very prosperous research area. In this regard, quaternary phosphonium salts have gained considerable attention as catalysts in many chemical transformations and synthetic chemistry. In this review, recently important advances on the properties, synthesis, and applications of quaternary phosphonium salts in both homogeneous and heterogeneous catalysis forms are summarized. We also discussed the asymmetric phosphonium salts in a wide range of applications in phase-transfer catalysis into enantioselective organic reaction.