Iridium/Acid Cocatalyzed Direct Access to Fused Indoles via Transfer Hydrogenative Annulation of Quinolines and 1,2-Diketones.

Herein, we present an unprecedented iridium/acid cocatalyzed construction of fused indoles via transfer hydrogenative annulation of nonactivated quinolines and 1,2-diketones. The products are assembled via initial reduction followed by selective coupling of 1,2-diketones with the N and C8 sites of the quinolyl skeleton. The developed synthetic method features operational simplicity, readily available feedstocks, applicability for streamline synthesis of functional molecules, high step and atom efficiency, and generation of water as the byproduct.