Formate-Mediated C-C Coupling of Aryl/Vinyl Halides and Triflates: Carbonyl Arylation and Reductive Cross-Coupling.

Catalytic methods for the intermolecular formate-mediated C-C coupling of Csp-X pronucleophiles beyond reductive Heck reactions (alkene hydroarylations) are catalogued. These methods include transfer hydrogenative reductive couplings of aryl/vinyl halides or triflates to carbonyl compounds (Grignard/NHK-type reactions), as well as reductive cross-couplings of two aryl/vinyl halide or triflate partners. These studies demonstrate that reactions traditionally associated with discrete Csp carbanions can be rendered catalytic and free from premetalated reagents or metallic reductants using sodium or potassium formate - abundant, low molecular weight sources of hydrogen.