Chemoselective Hydrogenation of Nitro Compounds with Supported Gold Catalysts

Abstract

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 H2 is used, the addition of soluble metals. Gold nanoparticles supported on TiO2 or Fe2O3 catalyzed the chemoselective hydrogenation of functionalized nitroarenes with H2 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.

One pot synthesis of cyclohexanone oxime from nitrobenzene using a bifunctional catalyst

“…No intermediate diazo products were detected. [17][18][19] The reaction sequence was confirmed by reacting cyclohexylaniline 4 at 60 ºC in the presence of Pd/C. In that case, dicyclohexylamine 5 was obtained with very high selectivity, as a primary product.…”

Hydrogenation over gold catalysts: The interaction of gold with hydrogen

“…Gold catalyzes various hydrogenation reactions such as the hydrogenation of alkenes (3)(4)(5)(6)(7)(8)(9)(10)(11)(12), alkadiens (13)(14)(15)(16)(17)(18) alkynes (13,(19)(20)(21)(22)(23)(24)(25), , -unsaturated carbonyl compounds and nitro compounds (47)(48)(49)(50)(51)(52)(53). In contrast to traditional hydrogenation catalysts such as platinum, palladium or ruthenium, which require modification, it often shows remarkable selectivities when multiple functional groups are present.…”

In situ loading of Cu2O nanoparticles on a hydroxyl group rich TiO2 precursor as an excellent catalyst for the Ullmann reaction

“…Nanocatalysis is an important part of nanoscience, materials science and chemistry [1][2][3][4]. Many nanoparticles have been used to catalyze a variety of chemical reactions.…”