A Comprehensive review of the Caged Phosphines: Synthesis, Catalytic Applications and Future Perspective

Phosphines have played an important and activating role in the rapid rise of the transition metal-catalysed processes and with the possibility of fine-tuning the electronic and steric properties of these ligands, several synthetic challenges have been overcome in the past decades leading to their application in academia and industry. Caged phosphines are one such class of phosphines having the phosphorus atom at the bridgehead of a cyclic cage and have exhibited excellent control of steric and electronic properties leading to their applications as ligands in a vast number of catalytic processes. This review provides an overview of the origin as well as the development that has taken place in this area of research and how the unique properties of these ligand systems could help fine-tune the reactivity. Critical analysis of the area reveals some lacunae that will also be highlighted to promote further development in this area of research.