Zirconium-hydride-catalyzed transfer hydrogenation of quinolines and indoles with ammonia borane

Abstract

Herein, by applying zirconium–hydride complex as the catalyst, the transfer hydrogenation of quinoline and indole derivatives with ammonia borane as a proton and hydride source is achieved. Up to 94% yield of the corresponding hydrogenated products was obtained with tolerance of various functional groups. Preliminary mechanistic studies revealed a concerted N–H and B–H activation reaction pathway.