Synthesis of a N-heterocyclic Olefin-Ligated Pd Complex [(NHO)Pd{[2-(CH3O)C6H4]3P}Cl2] as a Catalyst for Suzuki-Miyaura Coupling

N-heterocyclic olefin (NHO) is known as a highly electron-donative ligand, but its application to metal catalysts has rarely been studied. In this study, we synthesized 2-methyleneimidazolidine ligands equipped with a bicyclic frameworks with the goal of developing a NHO-ligated Pd catalyst. These synthesized [(NHO)PdCl(mu-Cl)](2) complexes had a phosphine co-ligand that proved effective as a catalyst for Suzuki-Miyaura coupling at ambient temperature. By optimizing the N-substituents of NHO ligands and a phosphine co-ligand, we developed a [(NHO)Pd{[2-(CH3O)C6H4](3)P}Cl-2] complex as a catalyst that shows good catalytic activity.