Iridium-Catalyzed Asymmetric Hydrogenation of Pyridazine Salts under Batch and Flow

Herein, we report an [Ir(COD)Cl]2/(R)-SunPhos-catalyzed asymmetric hydrogenation of pyridazine salts to construct chiral hexahydropyridazines. The reaction tolerates a wide range of substituents, delivering products in up to 97% yield with 97% ee under mild reaction conditions. Simultaneously, the gram-scale synthesis, continuous-flow operation, and good catalyst turnover (TON up to 3720 with 94% ee at S/C = 4000; TOF up to 155 h–1) further underscored the practicality of this methodology. Collectively, this operationally simple, scalable, and sustainable protocol provides an efficient platform for valuable N-heterocycles featuring chiral hexahydropyridazine cores.