One- and Two-Electron Carbon-Halide Bond Activation at a Phosphorus Center

The activation of small molecules by main-group elements has garnered significant attention as a potential alternative to transition metal catalysis. While transition metals excel in switching between single-electron (1e) and two-electron (2e) pathways due to their accessible d-orbitals, such switchability remains uncommon for main-group elements. In this work, we report the phosphorus-centered selective activation of various organohalides by phosphorus-atom transfer reaction of metallophosphanorcaradiene complex, which presents four distinct modes, S_N2 or S_NAr-type substitution, E2 elimination, or reductive radical coupling via halogen-atom transfer. These reactivities selectively show 1e or 2e pathways depending on the substrate, mimicking oxidative addition and radical activation steps traditionally reserved for transition metals. These divergent modes of reactivity are enabled by the substantial orbital interactions between the single phosphorus atom center and [Cp*(Idipp)(CO)Ru] fragment, which can be viewed as a metalloligand, allowing for switchable reactivities between 2e and 1e pathways. Furthermore, this platform enables the modular synthesis of phosphines bearing three different substituents through a "P + 2E + Nu" strategy, establishing a new phosphorus-atom transfer route to organophosphorus molecules (E = electrophile; Nu = nucleophile).