Highly Active Pd-PEPPSI Complexes for Suzuki-Miyaura Cross-coupling of Aryl Chlorides: an Investigation on the Effect of Electronic Properties

Three new Pd-pyridine enhanced precatalyst preparation stabilization and initiation(PEPPSI) complexes with halogen groups on the N-heterocyclic carbene and pyridine were prepared. Their structures have been clearly characterized by nuclear magnetic resonance spectroscopy and X-ray single-crystal diffraction. The effects of the electronic properties of halogen groups on the catalytic activity in the Suzuki-Miyaura cross-coupling of aryl chlorides were investigated. These Pd-PEPPSI complexes could catalyze the cross-coupling reaction efficiently with a low catalyst loading(0.05%, molar ratio) at room temperature and the products were obtained in high yields.