Chemoselective Hydrogenation of Nitro Compounds with Supported Gold Catalysts

The selective reduction of a nitro group when other reducible functions are present is a difficult process that often requires stoichiometric amounts of reducing agents or, if H 2 is used, the addition of soluble metals. Gold nanoparticles supported on TiO 2 or Fe 2 O 3 catalyzed the chemoselective hydrogenation of functionalized nitroarenes with H 2 under mild reaction conditions that avoided the accumulation of hydroxylamines and their potential exothermic decomposition. These chemoselective hydrogenation gold catalysts also provide a previously unknown route for the synthesis of the industrially relevant cyclohexanone oxime from 1-nitro-1-cyclohexene.