Optimization and Mechanistic Studies of the Electrochemical Dimerization of Primary Alkyl-Bromides and Benzylic Chlorides Utilizing a Nickel(II)/Terpyridine Catalytic System.

内容摘要

Electrochemical reductive homo-coupling of alkyl halides provides a sustainable alternative to metal-powder-based protocols. We report a nickel-catalyzed system operating under mild electroreductive conditions that delivers C(sp3)-C(sp3) dimers efficiently using either a sacrificial anode or a metal-free graphite/DIPEA setup. Various Ni(II) precursors combined with terpyridine ligand proved effective, enabling the dimerization of a range of primary alkyl halides and benzylic substrates. Electrochemical analysis highlights the role of the initial reduction of the Ni(II) precatalyst and reveals a strong influence of the counter-anion on nickel speciation. In particular, lithium halides enhance reactivity by altering the coordination environment of nickel. These findings establish a practical and tunable platform for electrochemical dimerization and clarify how ligand and salt effects govern catalytic efficiency.