Room-Temperature Chemoselective Reduction of 3-Nitrostyrene to 3-Vinylaniline by Ammonia Borane over Cu Nanoparticles

Abstract

We report a new strategy of controlling catalytic activity and selectivity of Cu nanoparticles (NPs) for the ammonia borane initiated hydrogenation reaction. Cu NPs are active and selective for chemoselective reduction of nitrostyrene to vinylaniline under ambient conditions. Their activity, selectivity, and more importantly, stability are greatly enhanced by their anchoring on WO 2.72 nanorods, providing a room-temperature full conversion of nitrostyrene selectively to vinylaniline (>99% yield). Compared with all other catalysts developed thus far, our new Cu/WO 2.72 catalyst shows much enhanced hydrogenation selectivity and stability without the use of pressured hydrogen. The synthetic approach demonstrated here can be extended to prepare various M/WO 2.72 catalysts (M = Fe, Co, Ni), with M being stabilized for many chemical reactions.

Ni3N as an Active Hydrogen Oxidation Reaction Catalyst in Alkaline Medium

“…This charge transfer decreases the electron density of Ni 3 N, making it more difficult to be oxidized. Enhanced oxidative resistance due to interfacial charge transfer observed by XPS was reported for other supported catalysts such as Cu/WO 2.72 . Whether the charge transfer is the cause of the downshift of the d‐band, or works in parallel to it, remains unclear.…”

Synthesis, characterization, and catalytic activity of half‐sandwich ruthenium complexes with pyridine/phenylene bridged NHC = E (NHC = N‐heterocyclic carbene, E = S, Se) ligands

“…[ 34–46 ] AB as a transfer hydrogenation source replace of hydrogen was used for nitro compounds reduction process due to its high volume/mass hydrogen density, non‐toxicity, and high stability. [ 47–50 ]…”

Commercially Available CuO Catalyzed Hydrogenation of Nitroarenes Using Ammonia Borane as a Hydrogen Source

“…[26] Significant progress has been made for the one-pot transfer hydrogenation of nitro compounds to the target amines. [27][28][29][30][31][32][33][34][35][36][37][38][39] Multiple reports have described nanoparticle-type catalysts that exhibit good activity, selectivity, and reusability for hydrogenation reactions; however, most of these are composed of at least two types of transition metals, [27][28][29][30][31][32] and even noble metals. [30][31][32][33][34]38,39] In general, these ultra-small metal nanoparticles are loaded onto special solid supports, such as graphene, [28,29] MOFs, [30] reduced graphene oxide, [31] nitrogen-doped graphene, [32] TiO 2 , [34] or N-doped porous carbon.…”

“…[35] For example, Sun and co-workers reported the chemoselective reduction of 3-nitrostyrene to 3-vinylaniline within 1.5 h using exquisitely designed Cu nanoparticles anchored on WO 2.72 nanorods. [36] Although these are significant advances, the requirement for supports and noble metals makes these catalysts less applicable to the industrial scale preparation of aromatic amines. Accordingly, there remains a need for the development of low-cost, readily available, and highly selective catalysts for the synthesis of amines via the reduction of nitro compounds.…”

“…Some substituted nitropyridines could also participate in the hydrogenation reaction, affording the corresponding amines in excellent yields (33)(34)(35). In addition, nitronaphthalene, 2-nitroquinoline, 4-(4-nitrobenzyl) pyridine, 5-nitro-1H-indole, and 1-(4-nitrophenyl)ethan-1-ol, could also function in this transformation, giving the target products (5,32,36,37). Although several nitroarene substrates were not suitable for this catalytic system ( Figure S1), the above experimental results showed that this catalytic protocol displays a preeminent substrate scope and application potential.…”