Aromatic tertiary amines are one of the most important classes of organic compounds in organic chemistry and drug discovery. It is difficult to efficiently construct tertiary amines from primary amines via classical nucleophilic substitution due to consecutive overalkylation. In this paper, we have developed a radical tandem C-N coupling strategy to efficiently construct aromatic tertiary amines from commercially available carboxylic acids and nitroarenes. A variety of aromatic tertiary amines can be furnished in good yields (up to 98%) with excellent functional group compatibility under mild reaction conditions. The use of two different carboxylic acids also allows for the concise synthesis of nonsymmetric aromatic tertiary amines in satisfactory yields. Mechanistic studies suggest the intermediacy of the arylamine-(TPP)Fe(III) species and might provide a possible evidence for an SH2 (bimolecular homolytic substitution) pathway in the critical C-N bond formation step. 

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Decarboxylative tandem C-N coupling with nitroarenes via SH2 mechanism

Herein, we constructed one-dimensional hollow nanofiber catalyst composed of tightly-packed multiphase metal oxides of Mn2O3  and Cu1.4Mn1.6O4  by electrospinning and tailored thermal treatment procedure. The characterization results comprehensively confirmed the special morphology and composition of various comparative catalysts. This strategy endows the catalyst with the abundant interfacial manner of component Mn2O3  and Cu1.4Mn1.6O4  nanocrystal. Impressively, the tuning thermal treatment renders tailored Cu(I) sites and surface oxygen species of the catalyst thus affording optimized oxygen vacancy for reinforced oxygen adsorption, while the concomitant enhanced lattice oxygen activity in the constructed composite catalyst ensures the higher catalytic oxidation ability. More importantly, the regulated proportion of oxygen vacancy and lattice oxygen in the composite catalyst was obtained in the best catalyst, benefiting to accelerate the reaction cycle. Compared to other counterparts obtained by different temperatures, the CMO-500 sample exhibited superior selective aerobic 5-hydroxymethylfurfural (HMF) oxidation to 2, 5-furandicarboxylic acid (FDCA, 96% of yield) in alkali-bearing aqueous solution using O2  at 120 °C, which was resulted from the above-mentioned composition optimization and interfacial engineering reinforced surface oxygen consumption and regeneration cycle. The reaction mechanism was further proposed to uncover the lattice oxygen and oxygen vacancy participating HMF conversion process.

Enabling efficient aerobic 5-hydroxymethylfurfural oxidation to 2,5-furandicarboxylic Acid in water by interfacial engineering reinforced Cu-Mn oxides hollow nanofiber.

Although metal-carbon combination has been demonstrated promotive efficiency in advanced oxidation process(AOP), multidimensional coupling by exploiting metal-carbon interaction, dual-metal redox cycle, and photothermal synergetic catalysis remains rare in AOP. Here,...

Carbon framework encapsulated CoMn2O4 spinel derived from electrospun nanofiber coupling with photothermal approach reinforces PMS activation to eliminate 2,4-dichlorophenol

Enabling room-temperature reductive C−N coupling of Nitroarenes: Combining homogeneous with heterogeneous synergetic catalysis mediated by light

Dioxomolybdenum(VI) complexes have been applied as efficient, inexpensive and benign catalysts to deoxygenation reactions of a diverse number of compounds in the last two decades. Dioxomolybdenum complexes have demonstrated wide applicability to the deoxygenation of sulfoxides into sulfides and reduction of N–O bonds. Even the challenging nitro functional group was efficiently deoxygenated, affording amines or diverse heterocycles after reductive cyclization reactions. More recently, carbon-based substrates like epoxides, alcohols and ketones have been successfully deoxygenated. Also, dioxomolybdenum complexes accomplished deoxydehydration (DODH) reactions of biomass-derived vicinal 1,2-diols, affording valuable alkenes. The choice of the catalytic systems and reductant is decisive to achieve the desired transformation. Commonly found reducing agents involved phosphorous-based compounds, silanes, molecular hydrogen, or even glycols and other alcohols.

Deoxygenation reactions in organic synthesis catalyzed by dioxomolybdenum(VI) complexes.

Interfacial engineering coupling with tailored oxygen vacancies in Co2Mn2O4 spinel hollow nanofiber for catalytic phenol removal

The construction of the C-N bond with nitroaromatics and boric acids using highly efficient and recyclable catalyst remains a challenging project. In this contribution, we have disclosed that the guest-host nanoporous MoO 3 confined in silica is efficient heterogeneous catalyst for C-N cross-coupling of nitroaromatics with aryl- or alkyl-boronic acids to deliver N -arylamines, and with desirable multiple reusability. Experimental results suggest that silica not only makes the Mo species be heterogenized in the confined mesoporous microenvironment but also conspicuously reduces the reaction induction period and regulates the chemical efficiency of the targeted product. The well-shaped MoO 3 @-m-SiO 2 catalyst exhibits improved catalytic performance both in yield and TON value contrast with that of homogeneous Mo catalysis, commercial Pd/C, or MoO 3 nanoparticals (NPs). This approach offers a brand-new avenue for the heterogeneous synthesis of valuable bioactive molecules.

Mengting Liu

Papers

Interfacial engineering coupling with tailored oxygen vacancies in Co2Mn2O4 spinel hollow nanofiber for catalytic phenol removal

Reductive C-N Coupling of Nitroarenes: Heterogenization of MoO3 Catalyst by Confinement in Silica.

Hierarchically structured Ag modified nanosilica constructed by micelle modification tactics delivers integrated catalytic and antibacterial activity