Iron‐Catalyzed Transfer Hydrogenation: Divergent Synthesis of Quinolines and Quinolones from ortho‐Nitrobenzyl Alcohols

Herein, we report the divergent synthesis of quinolines and quinolones via a transfer hydrogenative condensation of ortho‐nitrobenzyl alcohols in one step. The reaction proceeded using the cyclopentadienone iron complex without any additional redox reagents. After transfer hydrogenation between ortho‐nitrobenzyl alcohols and secondary alcohols, the subsequent Friedländer annulation affords polysubstituted quinoline products in 22–90% (39 examples). The developed method was also applied to synthesize quinolones by using primary alcohols instead of secondary alcohols (12 examples). The obtained quinoline products were converted into several drug candidates to demonstrate its synthetic potential.