A Ni(I)/Ni(III) Catalytic Cycle for Sustainable C–S Bond Formation via Mechano-Piezoelectric Electron Transfer

The activation of inert C–Cl bonds in heteroaromatic chlorides for C–S coupling remains a significant challenge in sustainable synthesis. Herein, we report a mechanochemical strategy that leverages piezoelectric BaTiO3 to in situ generate active Ni(I) species via force-induced electron transfer, enabling C–S cross-coupling of N-heteroaromatic chlorides with disulfides under solvent-free aerobic conditions. This approach establishes a Ni(I)/Ni(III) catalytic cycle that operates with minimal zinc reductant and piezoelectric material, eliminating the need for stoichiometric metal-based reductants. This method demonstrates enhanced substrate tolerance afforded by mechanochemistry, including tolerance toward fused-ring systems and biomolecules, along with the recyclability of BaTiO3, consistent with green chemistry principles. Mechanistic studies support a pathway involving disulfide activation to form organozinc sulfides and Ni(I)-mediated oxidative addition. This work demonstrates the power of mechano-piezoelectric synergy to unlock elusive redox manifolds in transition-metal catalysis.