Nickel Catalyzed Electrochemical C(sp3)-C(sp2) Cross-Coupling Reactions of Benzyl Trifluoroborate and Organic Halide.

Herein, we report redox neutral electrochemical C(sp2)-C(sp3) cross-coupling reactions of bench-stable aryl halide or β-bromostyrene (electrophiles) and benzylic trifluoroborate (nucleophiles) using non-precious, bench-stable NiCl2•glyme/polypyridine catalysts in an undivided cell configuration under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reactions were confirmed by 50 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Its potential applications were demonstrated by electrosynthesis and late-stage functionalization of pharmaceuticals, and natural amino acid modification. Furthermore, to testify practical industrial adoption, three electrochemical C-C cross-coupling reactions were demonstrated at gram-scale in a flow-cell electrolyzer. An array of chemical and electrochemical studies mechanistically indicates that the studied electrochemical C-C cross-coupling reactions proceed through an unconventional radical trans-metalation mechanism. The presented Ni-catalyzed electrochemical C(sp2)-C(sp3) cross-coupling paradigm is highly productive and expected to find wide-spread applications in organic synthesis.