Controlled DefluorinativeCarboxylation Cascade ofSterically Hindered CF₃‑Alkenes with Formate Saltvia Photocatalysis

A controlled cleavage of double C–F bonds in sterically hindered tetrasubstituted CF₃-alkenes using formate salt has been achieved through a photoinduced electron transfer approach. Diverse γ-branched multifunctionalized <i>gem</i>-difluoroalkenes and α-fluoroacrylic acids are obtained sequentially via hydrodefluorination and C–F bond carboxylation with good-to-high yields. Precisely controlling the quantity of formate salt and the reaction time is crucial for obtaining divergent defluorinative products. Formate serves as the C1 source, hydrogen donor, and reducing agent.