Divergent Coupling of Anilines and Enones by Integration of C−H Activation and Transfer Hydrogenation

Cp*RhIII/IrIII complexes are known to play important roles in both C−H activation and transfer hydrogenation (TH). However, these two areas evolved separately. They have been integrated in redox‐ and chemodivergent coupling reactions of N‐pyridylanilines with enones. The iridium‐catalyzed coupling with enones leads to the efficient synthesis of tetrahydroquinolines through TH from iPrOH. Counterintuitively, iPrOH does not serve as the sole hydride source, and the major reaction pathway involves disproportionation of a dihydroquinoline intermediate, followed by the convergent and iterative reduction of quinolinium species. Celebrating their differences: C−H activation and transfer hydrogenation were integrated under IrIII/RhIII catalysis for the coupling of N‐pyridylanilines and enones. The course of the reductive coupling could be changed by the appropriate choice of catalyst and reaction conditions to enable the synthesis of tetrahydroquinolines or homoallylation products (see scheme).