Recent Advances in the Pd‐Catalyzed Coupling of Arylhydrazines and Ammonium Salts via C−N Bond Cleavage

Abstract Both arylhydrazines and quaternary ammonium salts are readily accessible or commercially available chemicals that show versatile reactivity in Pd‐catalyzed coupling reactions via C−N bond cleavage. A tremendous array of coupling reactions involving reaction partners such as organoborons, aryl silanes, alkenes, alkynes, arylation or alkylation reagents in C−H functionalization and carbonylation reactions are summarized, in which arylhydrazines or quaternary ammonium salts function as aryl or alkyl donors. This account mainly focuses on recent advances in Pd‐catalyzed coupling reactions with arylhydrazines or quaternary ammonium salts via C−N bond cleavage, including mechanistic elucidations.