Transfer Hydrogenation of Aromatic Nitro Compounds Using Polymer‐Supported Formate and Pd‐C

A Green Reduction of Aromatic Nitro Compounds to Aromatic Amines Over a Novel Ni/SiO2 Catalyst Passivated with a Gas Mixture

“…High selectivity of aromatic amines is achieved while using the passivated Ni/SiO 2 as catalyst, and the probable reason is that the passivated Ni/SiO 2 catalyst has lower activity and doesn't destroy sensitive groups in comparison with other reported catalysts, such as Raney Ni, Pd(0) and Pd/C [5,6,8,11,13,27,35,36]. Different from that reported in some previous work [35], higher selectivity for aromatic aldehydes is obtained (entry 15,16) using the passivated Ni/SiO 2 catalyst.…”

“…The important developed catalytic systems are listed as follows, MCM-41-silylamine palladium(II)/THF [5],poly(4-vinylpyridine-co-N-vinylpyrrolidone)-Pd (0)/EtOH [6], Au/SiO 2 /EtOH [7], nanosized nickel/EtOH [8], Au-Pt-NH 2 -Si-MCM-41/CH 3 OH [9], Au/Al 2 O 3 [10], silica sol-gel encaged Pd-[Rh(cod) Cl] 2 /n-heptane [11], nanosized NiCoB amorphous alloy/ CH 3 OH [12], PSF-Pd/DMF [13], Ni/SiO 2 [14], PVPA-Pd/ EtOH/KOH [15], zero-valent iron powder/CH 3 CN/phosphate buffer [16], Au/TiO 2 or Au/Fe 2 O 3 [17,18], Cocolliod or NiPd-colliod/THF [19], Au/ZrO 2 /EtOH [20], LaMO 3 /KOH/propan-2-ol [21], La 1-x Sr x FeO 3 /KOH/propan-2-ol [22], Co(II)/mesoporous aluminophosphate/KOH/ iPrOH [23], Ni-MCM-41/iPrOH/KOH [24], hydrazine hydrate/ferrihydrite/EtOH [25], Polymer-Supported Formate and Magnesium/MeOH [26], Polymer-Supported Formate/Pd-C/ MeOH [27], CeO 2 -SnO 2 /hydraine/MeOH [28], Heteropolyacid/MeOH/N 2 H 4 [29], RhCl 3 /CO/H 2 O [30], Ru 3 (CO) 12 [49]. However, some difficulties is still existed, such as (1) seriously environmental pollution from residue, (2) expensive or sensitive to air, (3) significant limitations based on safety and handling considerations, (4) strong acidic or alkaline media, (5) the reaction conditions of most of these methods can destroy many sensitive functional groups.…”

“…Nowadays, numerous methods for the reduction of aromatic nitro have been reported in the literatures, such as catalytic hydrogenation [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], catalytic transfer hydrogenation [21][22][23][24][25][26][27][28][29], CO/H 2 O conditions [30][31][32] and other reduction systems [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. The important developed catalytic systems are listed as follows, MCM-41-silylamine palladium(II)/THF [5],poly(4-vinylpyridine-co-N-vinylpyrrolidone)-Pd (0)/EtOH [6], Au/SiO 2 /EtOH [7], nanosized nickel/EtOH [8], Au-Pt-NH 2 -Si-MCM-41/CH 3 O...…”

Reduction of Nitroarenes via Catalytic Transfer Hydrogenation Using Formic Acid as Hydrogen Source: A Comprehensive Review

“…Other variable are the energy source such as heating, UV light irradiation and the use of a stainless steel ball at 30 Hz, the use of base and solvent [69–70] . Most of reported protocols are focusing on the investigation of catalyst consisted of a palladium anchored on support material including carbon (Pd/C), SiO 2 (Pd/SiO 2 ), polyurea support material [Pd 0 EnCat], aminomethyl‐polystyrene resin, supported zirconium phosphate (Pd/ZrP), Pd−Ag composite, silicon nano‐particle (Pd/Si), Vulcan carbon support N‐XC72R (Pd/N‐XC72R) and PdNi/mCN [56,62–66,68–70] . The use of support loaded palladium metal facilitats the access of substrate to hydrogen source due to that all reaction components (nitro‐arene, catalyst and formate, and water as hydrogen source) are placed onto support by adsorption as well as generate basic pocket sites that facilitate the catalytic activity in absence of external base.…”

Chemoselective reduction of aldehydes by ruthenium trichloride and resin-bound formates

“…Danks et al also carried out reduction of alkyl cinnamates using polymer supported formate and catalytic RhCl(PPh 3 ) 3 (2.5 mol%) under microwave irradiation [ 25 ]. Pd-catalyzed transfer hydrogenation of nitroarenes using recyclable polymer-supported formate has been investigated by Abiraj et al [ 26 ]. Neither of these conditions were, however, effective in reducing aryl ketones.…”