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.