Preparation of Phosphinated Polymer‐Incarcerated Palladium and Its Application to CN and CC Bond‐Forming Reactions

Phosphinated polymer-incarcerated (PI) Pd catalysts were prepared by immobilization of palladium with phosphinated polymers by using the PI method. The phosphinated PI Pd catalysts showed good catalytic activity without externally added phosphine ligands in the amination of aryl halides for C-N bond-forming reactions, as well as in Suzuki-Miyaura and Sonogashira coupling. No leaching of palladium from the immobilized Pd was observed by fluorescence X-ray analysis. Furthermore, it was found that immobilization of Pd by the PI process facilitated the suppression of poisoning of the metal by amines. These effects can be ascribed to stabilization of the catalyst by both the phosphine moieties and the benzene rings in the swollen polymer support. The phosphinated PI Pd catalysts could also be recovered by simple filtration and reused several times without leaching of palladium in both the amination and Suzuki-Miyaura coupling reactions.