Fc‐<scp>JosiPhos</scp>‐Enabled Low‐Loading Pd Catalysis: A Modular C–N Cross‐Coupling Strategy for Arylhydrazines Synthesis

Comprehensive Summary A palladium catalytic system incorporating novel Fc‐JosiPhos ligands enables efficient C–N bond formation with diverse (hetero)aryl halides under low palladium loading (0.1 mol%). We rationally designed novel ferrocenyl phosphine‐derived JosiPhos ligands (L1–L3). These ligands incorporate a ferrocenyl group providing greater steric bulk than tert ‐butyl or cyclohexyl and superior electron donation to cyclohexyl, along with a tunable side chain. They delivered excellent yields in the catalytic coupling of challenging (hetero)aryl chlorides with hydrazine. The scalable synthesis of arylhydrazines (5 mmol scale) and subsequent cyclization to pyrazoles (65%–91% yields) highlights their potential for industrial conversion. Furthermore, the modularity of this strategy supports late‐stage pharmaceutical functionalization, exemplified by TRPC inhibitor intermediate.