An Active, General, and Long-Lived Palladium Catalyst for Cross-Couplings of Deactivated (Hetero)aryl Chlorides and Bromides with Arylboronic Acids
摘要:
An active, general, and long-lived palladium catalyst for Suzuki-Miyaura reactions of aryl and heteroaryl chlorides deactivated by steric hindrance, electron richness, and coordinating functional groups is reported. In reactions of arylbromide bearing two o-tert-butyl substituents, C(sp(3))-H arylation of the tert-butyl group, rather than the Suzuki-Miyaura reaction, proceeded in excellent yield. The key to the success of the reactions was the development of biphenylene-substituted dicyclohexylruthenocenylphosphine (CyR-Phos) as a supporting ligand.
hindered biaryls efficiently, a series of NHC-Pd(II)-azole complexes bearing sterically hindered ligands were synthesized and characterized. The steric environment effect as well as the electronic effect of the azole ligands has been assessed. All these complexes were applied in the Suzuki−Miyaura cross-coupling reaction of sterically hindered arylchlorides with low catalysts loadings (0.1 mol %) under