Palladium-catalyzed Suzuki-Miyaura cross-coupling of various aryl halides using ortho-alkyl-substituted arylphosphanes and (ortho-alkylphenyl)-alkylphosphanes under microwave heating

摘要

Mono- and dinuclear palladium(II) chloride complexes of various ortho-alkyl-substituted aryl- and alkylphosphanes were prepared. Subsequently, these were characterized by H-1 NMR and P-31(H-1) NMR spectroscopy, X-ray crystallographic studies and mass spectroscopy. The palladium complexes were screened as potential catalysts for the microwave-assisted Suzuki-Miyaura coupling reaction of several aryl halides under aerobic conditions. A preliminary study showed that excellent results can be obtained even for electron-rich bromides and unactivated aryl chlorides with an optimized solvent, base and catalyst loading using specific phosphane ligands. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).