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

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.