Nickel-Catalyzed Cyanation of Aryl Halides.

Nickel-catalyzed cyanation of aryl halides has emerged as a powerful and sustainable method for the synthesis of aryl nitriles-valuable motifs widely found in pharmaceuticals, agrochemicals, and functional materials. Compared to traditional cyanation methods that involve harsh conditions and toxic reagents, nickel catalysis enables mild, efficient, and versatile transformations. This review systematically summarizes recent advances in this field, categorized by different cyanide sources, including metal cyanides (NaCN, KCN, Zn(CN)2, K4[Fe(CN)6]) and non-metal or organic cyanide sources (e.g., MeCN, nitriles, BrCN, CO2/NH3). Key developments in catalyst systems, ligand design, mechanistic insights, and green chemistry aspects are highlighted. Remaining challenges and future directions are also discussed.