Redox-Active Sulfonyl Hydrazones as Programmable Sulfur Transfer for Nickel-Catalyzed C–S Coupling with Organic Halides

The utilization of hydrazones as carbon or nitrogen sources in transition-metal-catalyzed synthetic chemistry has been well developed; however, their application as electrophilic sulfur cation surrogates remains uncharted territory. Herein, we report the unexpected discovery that sulfonyl hydrazones serve as programmable sulfur transfer in nickel-catalyzed C–S coupling with a broad range of organic halides. This method forges the nickel catalytic cycle toward selective C–S cross-coupling while effectively suppressing the competing formation of conventional C–C coupling products. Mechanistic studies indicate that the success of this strategy stems from the favorable reduction potential imparted by the electron-withdrawing SO 2 R group, which enables manganese to reduce the hydrazones in situ, generating key electrophilic sulfur species to engage in a distinctive nickel catalytic cycle that favors C–S over C–C bond formation.