ortho,ortho'-Substituted KITPHOS Monophosphines: Highly Efficient Ligands for Palladium-Catalyzed C-C and C-N Bond Formation

摘要

ortho,ortho'-Substitution of the phos-phinoalkyne-derived aryl ring in KITPHOS (11-di-cyclohexylphosphmo-12-phenyl-9,10-ethenoanthra-cene) monophosphines enhances the performance of this class of ligand in palladium-catalyzed Suzuki-Miyaura cross-couplings and Buchwald-Hartwig aminations, compared with their unsubsti-tuted and mono-substituted counterparts. An alternative complementary synthesis of KITPHOS monophosphines has been developed and two new members of this family, 2,6-Me2-KITPHOS [11-di-cyclohexylphosphino-12-(2,6-dimethylphenyl)-9,10-ethenoanthracene] and 2,6-(MeO)2-KITPHOS [11-dicyclohexylphosphino-12-(2,6-dimethoxyphenyl)-9,10-ethenoanthracene], have been prepared; palladium complexes of both are highly efficient catalysts for C-C and C-N bond formation with a range of electron-rich and electron-poor aromatic chlorides as well as heteroaryl chlorides.