Recent Advances in Nickel-Catalyzed C–S Bond Formation: Catalytic Strategies, Mechanistic Insights, and Sulfur Sources

This mini-review summarizes recent developments in nickel-catalyzed C–S bond formation, covering conventional cross-coupling, radical, photoredox-assisted, ligand-engineered, and sustainable catalytic strategies. The review focuses on sulfur-source activation and its application to C–S bond construction, including challenging C(sp3)–S coupling. The literature is organized according to sulfur-source classes and corresponding synthetic strategies. Comparative tables summarize representative systems by sulfur source, nickel catalyst, reaction type, conditions, mechanistic features, advantages, and limitations. Particular attention is given to catalytic pathways, nickel oxidation states, radical intermediates, ligand effects, and sulfur-source activation in studies published primarily between 2022 and 2025. Emerging photoredox/Ni dual catalysis and mechanochemical nickel catalysis are also discussed.