Abstract
Rhodium(Ⅲ)-catalyzed C-H couplings of arenes with alkenes are among the most powerful methods for C-C bond formation.For these transformations,subtle manipulation of ancillary ligands can lead to dramatic changes in reactivity and selectivity.However,detailed mechanistic studies concerning the ligand effects are rare.In this study,we investigated the origin of ligand-controlled product-selectivity in rhodium(Ⅲ)-catalyzed C-H couplings of arenes with alkenes,using a series of well-defined[CpⅩRhⅢ]complexes that feature electronically or sterically distinct CpⅩ(Cp(η5-C5H5),CpCF3(η5-C5Me4CF3)and Cp*(η5-C5Me5))ligands.A combination of experimental and theoretical investigations showed that(ⅰ)rhodium hydride species containing the electron rich Cp*ligand can undergo reinsertion of the alkene,thereby allowing rhodium-walking,(ⅱ)rhodium hydride species involving the electron-deficient Cp or CpCF3 ligands prefer reductive elimination rather than alkene insertion.These findings offer valuable in-sights on future rational catalyst design for selective arene-alkene cross coupling reactions.
基金项目
国家自然科学基金(21772162)
国家自然科学基金(21772165)
国家自然科学基金(22171237)
国家自然科学基金(22071208)
Youth Innovation foundation of Xiamen(3502Z20206058)
维普
万方数据