Controllable Chemodivergent Synthesis of α-Trifluoromethyl Boronates and gem-Difluoroalkenyl Boronates via Photoredox 1,2-Boron Migratory Carbonylation

Abstract

Fluorinated organoborons are highly valuable building blocks in drug discovery and materials science. However, the direct and step-economic synthesis of these complex structures remains a major challenge. Herein, we report a visible-light-driven, transition-metal-free chemodivergent borocarbonylation of α-trifluoromethyl styrenes. This multicomponent platform precisely controls the ultimate fate of the transient α-CF₃ benzylic radical. Under catalyst-free conditions, an electron donor-acceptor (EDA) complex with Hantzsch ester drives the radical cascade and a subsequent hydrogen atom transfer (HAT) to yield α-trifluoromethyl boronates. Alternatively, an Eosin Y/PMP photoredox system promotes a single-electron transfer (SET) and subsequent β-fluoride elimination to afford gem-difluoroalkenyl boronates. Overall, this strategy successfully manages the kinetic challenges of multi-step radical trapping, providing a practical and programmable platform to construct densely functionalized fluorinated organoborons.