Chiral phosphonium ion-pairing catalysis: From structural innovation to asymmetric synthesis

Chiral phosphonium salt catalysis has emerged as a crucial component of asymmetric ion-pairing catalysis, demonstrating growing significance in the field of asymmetric catalytic synthesis. With the unique structural features and outstanding catalytic properties, chiral phosphonium salts can excel in a wide variety of asymmetric reactions, exhibiting excellent catalytic performance and remarkable stereocontrol. Researchers have successfully developed various types of chiral phosphonium salt catalysts, including 1,1′-binaphthyl-based phosphonium salts, chiral diamine-derived P-spirotetraaminophosphonium salts, amino acid-derived bifunctional phosphonium salts, and peptide-based multifunctional phosphonium salts. This review comprehensively surveys two decades of advances in chiral phosphonium ion-pairing catalysis, encompassing the rational design strategies, synthetic approaches, wide-ranging utility in various asymmetric reactions, as well as practical applications in the construction of diverse chiral skeletons. Meanwhile, we delve into the catalytic mechanisms in multiple asymmetric reactions. Drawing upon a thorough synthesis of the present landscape, we additionally present a forward-looking perspective on the trajectory of this field’s future development. The ultimate goal is to spark innovative research endeavors, promote the creation of chiral phosphonium salts with novel skeletal frameworks, and the development of new catalytic systems, thereby further advancing the widespread application and vigorous development of chiral phosphonium ion-pairing catalysis.