“Cage‐Like” Phosphines: Design and Catalytic Properties

The need to design organocatalysts or water‐soluble catalysts for a number of reactions of industrial interest helps explain the renewed interest in ligands which allow such reactions to take place. Among them, “cage‐like” phosphines, known for some time, offer new perspectives as also do their corresponding metal transition complexes. The role of some of these ligands, such as Verkade‐type bases, 1,3,5‐triaza‐7‐phosphatricyclo[3.3.1.1]decane (PTA), 2,4,10‐trimethyl‐1,2,4,7,10‐hexaaza‐3‐phosphatricyclo[3.3.1.1 3,7 ]decane (THPA), and tris(1,2‐dimethylhydrazino)diphosphine (THDP), as central tools with broad functional group tolerance for CC, CO, CN bond formation, halogen exchange reactions, isomerization of allylic alcohols, cycloisomerization as well as Kharasch reactions are highlighted with selected examples.