Room-Temperature Rh(I)-Catalyzed P(III)-Directed C–H Bond Alkylation: Enhanced Reactivity through Ligand Acceleration

Despite the potential of Rh­(I)-catalyzed trivalent phosphorus-directed C–H functionalizations to diversify phosphorus-containing molecules, the requirement for harsh reaction conditions has limited its broader application. In this study, we introduce a ligand-accelerated catalysis approach that enables room-temperature C–H bond alkylation of biarylphosphines using a Rh­(I) catalyst. Through kinetic investigation, we identified tris(4-trifluoromethylphenyl)­phosphine as a privileged ligand that significantly enhances overall processes including catalyst stability and regeneration. Our NMR mechanistic studies revealed the formation of a Rh–H intermediate, providing direct evidence for an oxidative addition pathway. This work expands the utility of Rh­(I)-catalyzed C–H functionalization under mild conditions and lays the groundwork for further development of ligand-accelerated strategies in other challenging catalytic processes, particularly those involving strong σ-donor directing groups, holding significant potential to broaden the chemical space of phosphorus-based compounds, with diverse applications.