Nickel-Catalyzed Reductive Cross-Coupling of N-Acyl and N-Sulfonyl Benzotriazoles with Diverse Nitro Compounds: Rapid Access to Amides and Sulfonamides

Abstract

Herein we report a Ni-catalyzed reductive transamidation of conveniently available N-acyl benzotriazoles with alkyl, alkenyl, and aryl nitro compounds, which afforded various amides with good yields and a broad substrate scope. The same catalytic reaction conditions were also applicable for N-sulfonyl benzotriazoles, which could undergo smooth reductive coupling with nitroarenes and nitroalkanes to afford the corresponding sulfonamides.

B2(OH)4-Mediated Reductive Transamidation of N-Acyl Benzotriazoles with Nitro Compounds En Route to Aqueous Amide Synthesis

“…To a solution of benzotriazole (1.0 g, 8.4 mmol) and the corresponding acid (1.0 mmol, 1.0 equiv) in CH 2 Cl 2 (10 mL) was added 1, 3-dicyclohexylcarbodiimide (2.6 g, 1.5 equiv) . The mixture was then stirred at room temperature for 15 h and monitored by TLC.…”

“…The compound was isolated as a white solid (44.0 mg, 67%) by flash column chromatography (petroleum ether/ethyl acetate = 6/1) …”

Manganese-mediated reductive N,N-dialkylation of nitroarenes: a dramatic NiI2 effect

“…16). 15–18 In addition, the use of nickel nano-powder (with 50 nm or 1 μm diameter) as the promoter could also deliver product 3a in 71% and 80% yields, respectively (entry 17). We envisioned that nickel nano-powder might react with 2a to form NiI 2 in situ .…”

“…(2) It can be applied for the formal total synthesis of the drug chlorambucil, as well as the facile late-stage functionalization of drugs and pesticides. (3) Of note, although nitroaromatics have been efficiently used in C–N bond forming reactions such as reductive cyclization, 14 monoalkylation, 15 arylation, 16 acylation, 17 and others 18 recently, our work represents the first highly chemoselective reductive dialkylation of cheap nitroaromatics with alkyl halides. (4) Furthermore, compared with previous elegant studies focusing on the monoalkylation of nitrobenezene, 15 the selective dialkylation in our study is non-trivial as it proceeds through a different intermediate and is able overcome both the problems of steric hindrance and chemoselectivity by avoiding the formation of the corresponding monoalkylation or quaternary ammonium salts.…”

Environmentally Benign Transamidation Protocol for Weakly Nucleophilic Aromatic Amines with N‐Acyl‐2‐piperidinones: Catalyst‐, Additive‐, Base‐ and Solvent‐Free Condition

“…For example, N-activation by acylation/tosylation, [12,5] N-activation-metal catalyzation, [5,9,13,14] amide bond twist, [4,15] and amide bond twist-metal catalyzation. [15,16] Most of these developed methods deploy either catalyst that is metals such as Ni, [10,[17][18][19] Pd, [9,20,21] Ce, [22,23] Fe, [24] Cu, [25] W [6] and lanthanides [26] or activating agents to realize transamidation. In metal-catalyzed reactions, metals have to be carefully removed to obviate metal toxicity especially in pharmaceuticals.…”