A unique combination of steric and electronic properties appears to determine the effectiveness of phosphanyl-substituted biphenyls as ligands in palladium-catalyzed aminations and Suzuki coupling of aryl chlorides at room temperature [Eq. (1)]. The oxidative addition step is greatly accelerated, and transmetalation (or Pd-N bond formation) and reductive elimination processes are facilitated. Use of these ligands allows for Suzuki coupling at very low catalyst loadings (as little as 10(-6) mol % Pd). R"=cyclohexyl, tert-butyl.
“A Highly Active Catalyst for the Room-Temperature Amination and Suzuki Coupling of Aryl Chlorides”, Angew. Chem. Int. Ed., 1999, 38(16), 2413-2416.