Metal-free Bronsted acid catalyzed transfer hydrogenation - New organocatalytic reduction of quinolines

The first metal-free Bronsted acid catalyzed hydrogenation of quinolines using Hantzsch dihydropyridine as the hydrogen source has been developed. This, so far unprecedented organocatalytic reduction of heteroaromatic compounds provides a variety of differently substituted 1,2,3,4-tetrahydroquinolines in excellent yields under mild reaction conditions using a remarkably low amount of Bronsted acid catalyst.