- In alkaline media, Fremy's salt oxidizes alkanols by a hydrogen atom transfer mechanism
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In aqueous alkali, Fremy's salt (potassium nitrosodisulfonate dimer), homolyses nearly exclusively to the monomer radical anion, nitrosodisulfonate (NDS). In this media, NDS almost quantitatively oxidizes benzyl alcohol (PhCH2OH) to benzaldehyd
- De, Piyali,Kumar, Dhurjati Prasad,Mondal, Amit Kumar,Mandal, Pulak Chandra,Mukhopadhyay, Subrata,Banerjee, Rupendranath
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- A Metal–Organic Framework as a Multiphoton Excitation Regulator for the Activation of Inert C(sp3)?H Bonds and Oxygen
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The activation and oxidization of inert C(sp3)?H bonds into value-added chemicals affords attractively economic and ecological benefits as well as central challenge in modern chemistry. Inspired by the natural enzymatic transformation, herein,
- Cai, Junkai,Cai, Wei,Du, Zenggang,Duan, Chunying,He, Cheng,Ji, Guanfeng,Wei, Jianwei,Zhao, Liang
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supporting information
(2021/11/27)
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- Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
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A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
- Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
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supporting information
p. 2048 - 2053
(2022/03/31)
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- Mild oxidation of benzyl alcohols to benzyl aldehydes or ketones catalyzed by visible light
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Induced by visible light, mild oxidation condition to prepare benzyl aldehydes or ketones have been developed by using bromotrichloromethane as photochemical oxidant. This method avoids high temperature, pressure and peroxidation with only visible light as the green driving force.
- Cheng, Dongping,Li, Xiaonian,Ren, Shujian,Xu, Xiaoliang
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supporting information
(2021/07/02)
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- An aerobic oxidation of alcohols into carbonyl synthons using bipyridyl-cinchona based palladium catalyst
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We have reported an aerobic oxidation of primary and secondary alcohols to respective aldehydes and ketones using a bipyridyl-cinchona alkaloid based palladium catalytic system (PdAc-5) using oxygen at moderate pressure. ThePdAc-5catalyst was analysed using SEM, EDAX, and XPS analysis. The above catalytic system is used in experiments for different oxidation systems which include different solvents, additives, and bases which are cheap, robust, non-toxic, and commercially available on the industrial bench. The obtained products are quite appreciable in both yield and selectivity (70-85%). In addition, numerous important studies, such as comparisons with various commercial catalysts, solvent systems, mixture of solvents, and catalyst mole%, were conducted usingPdAc-5. The synthetic strategy of oxidation of alcohol into carbonyl compounds was well established and all the products were analysed using1H NMR,13CNMR and GC-mass analyses.
- Cheedarala, Ravi Kumar,Chidambaram, Ramasamy R.,Siva, Ayyanar,Song, Jung Il
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p. 32942 - 32954
(2021/12/02)
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- Integration of Earth-Abundant Photosensitizers and Catalysts in Metal-Organic Frameworks Enhances Photocatalytic Aerobic Oxidation
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We report here the construction of two metal-organic frameworks (MOFs), Zr6-Cu/Fe-1 and Zr6-Cu/Fe-2, by integrating earth-abundant cuprous photosensitizers (Cu-PSs) and Fe catalysts for photocatalytic aerobic oxidation. Site isolation and pore confinement stabilize both Cu-PSs and Fe catalysts, while the proximity between active centers facilitates electron and mass transfer. Upon visible light irradiation and using O2 as the only oxidant, Zr6-Cu/Fe-1 and Zr6-Cu/Fe-2 efficiently oxidize alcohols and benzylic compounds to afford corresponding carbonyl products with broad substrate scopes, high turnover numbers of up to 500 with a 9.4-fold enhancement over homogeneous analogues, and excellent recyclability in four consecutive runs. Control experiments, spectroscopic evidence, and computational studies revealed the photo-oxidation mechanism: Oxidative quenching of [Cu-PS]? by O2 affords [CuII-PS], which efficiently oxidizes FeIII-OH to generate a hydroxyl radical for substrate oxidation. This work highlights the potential of MOFs in promoting earth-abundant metal-based photocatalysis.
- Feng, Xuanyu,Pi, Yunhong,Song, Yang,Xu, Ziwan,Li, Zhong,Lin, Wenbin
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p. 1024 - 1032
(2021/01/26)
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- Metal-free selective reduction of acid chlorides to aldehydes using 1-hydrosilatrane
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This work uses 1-hydrosilatrane – an accessible and easy-to-handle reducing reagent – to selectively reduce acid chlorides to aldehydes. This metal-free reduction proceeds rapidly at ambient temperature in the presence of N-methylpyrrolidine, efficiently producing aldehydes in up to 54% yield and with the balance largely remaining as starting material. No over-reduced alcohol product is observed.
- Adler, Marc J.,Azam, Fawwaz,Raveenthrarajan, David
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supporting information
(2021/10/29)
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- Radical-mediated aerobic oxidation of substituted styrenes and stilbenes
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A 2,2-azobis(isobutyronitrile)-catalyzed oxidative cleavage of alkenes with molecular oxygen as the oxidant was described. Carbonyl compounds and oxiranes were obtained in moderate yield under mild conditions. This study provided useful insights into the mechanism of aerobic oxidative cleavage of alkenes.
- Aman, Hasil,Chiu, Wei-Hua,Chuang, Gary Jing,Liu, Pin-Heng
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supporting information
p. 20103 - 20106
(2021/12/02)
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- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
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A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
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p. 1962 - 1970
(2021/01/25)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- Aryl aldiketone and synthesis method thereof
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The invention discloses an aryl aldehyde ketone and a synthesis method thereof, wherein an aryl aldehyde is synthesized from cheap olefin as a raw material. A commercially available inexpensive olefin is used as a raw material, ether is used as an additive, molecular oxygen serves as a sole oxidizing agent, water is used as a solvent, and the aldehyde and ketone are synthesized by column chromatography under a photocatalytic condition. The invention has the advantages of mild reaction conditions, green and environmental protection, simple experimental operation, good reaction selectivity, high product yield and the like.
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Paragraph 0016
(2021/09/26)
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- Method for generating benzaldehyde by catalyzing alpha-monosubstituted styrene to be oxidized by N-hydroxyphthalimide
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The invention discloses a method for generating benzaldehyde by catalyzing alpha-mono-substituted styrene to be oxidized through N-hydroxyphthalimide. According to the method, N-hydroxyphthalimide isused as a catalyst, oxygen is used as an oxidizing agent, and an alpha mono-substituted styrene compound is oxidized in an organic solvent to obtain the benzaldehyde derivative. The method has the advantages of simple reaction operation, low cost, mild conditions, high yield, no heavy metal pollution and the like.
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Paragraph 0054-0056
(2021/01/24)
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- A highly stable metal-organic framework with cubane-like clusters for the selective oxidation of aryl alkenes to aldehydes or ketones
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Triazine derivatives, a class of electron-deficient π-conjugated molecules with high photochemical activity and excellent luminescent characteristics, have been utilized as a kind of electron-acceptor for the construction of molecular cages, luminescent and photochromic materials. In this paper, a novel and highly stable MOF with cubane-like clusters, [Co4(SO4)3(F)3(tpt)2(tatb)] (1) (tpt = 2,4,6-tris-(4-pyridyl)-1,3,5-triazine, H3tatb = 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid), has been successfully synthesized based on a triazine derivative, and possesses unprecedented sulfate- and fluoride-bridged cubane-type tetranuclear cobalt clusters and a 3D + 3D → 3D open framework. Compound1shows a rather high BET surface area and exhibits excellent thermal stability and high chemical stability in common solvents and even in acidic or basic solutions (in a pH range from 4 to 12). Moreover, catalytic measurements show that compound1is an excellent heterogeneous catalyst for the selective oxidation of aryl alkenes to aldehydes or ketones with conversions of 97%.
- He, Chixian,Liu, Jiaming,Liu, Jian-Jun,Liu, Teng,Shen, Xianfu,Shen, Xiang
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p. 4667 - 4673
(2021/07/11)
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- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
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The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0057-0058; 0089-0090
(2021/06/06)
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- Ferric ion concentration-controlled aerobic photo-oxidation of benzylic C–H bond with high selectivity and conversion
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A Fe(III)-promoted highly selective photo-oxidation of benzylic C–H bond delivering relative carbonyl products is reported. By altering the concentration of ferric salt, methylarenes can be selectively oxidized under UV irradiation to furnish aromatic aldehydes or acids, respectively. By this protocol, the oxidation of ethylarenes provides the corresponding acetophenones. The reaction is inferred to involve divergent pathways in different concentrations of catalyst for the alternative selectivity between aldehydes and aicds. The reusable catalyst, high conversion and selectivity make this oxidation a green and economic protocol for the synthesis of aromatic carbonyl compounds.
- Bu, Hongzhong,Gu, Jiefan,Li, Yufeng,Ma, Hongfei,Wan, Yuting,Wu, Zheng-Guang,Zhang, Weijian,Zhou, Ying'ao,Zhu, Hongjun
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- One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
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Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
- Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
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supporting information
p. 18150 - 18155
(2021/12/09)
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- Zirconium-based metal-organic framework as an efficiently heterogeneous photocatalyst for oxidation of benzyl halides to aldehydes
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The development of efficient heterogeneous catalysts for fine chemical synthesis is critical for practical applications. Herein, for the first time, the zirconium-based metal-organic framework (UiO-66-NH2) is applied as an efficiently heterogeneous photocatalyst for conversion of benzyl halides to corresponding aldehydes with high selectivity (about 80 %) and conversion (up to 99 %) in the presence of oxygen and DMF as solvent. Through a series of experiments and analysis, the reaction mechanism is proposed to involve nucleophilic attack of the N-oxide. This study provides a general, environmental and high selective method to prepare benzaldehydes and broadens the application fields of UiO-66-NH2.
- Xue, Ping,Huang, Jiming,Lin, Liguang,Li, Rong,Tang, Mi,Wang, Zhengbang
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- Oxidation of alcohols using an oxoammonium salt bearing the nitrate anion
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A methodology for the oxidation of alcohols to the corresponding carbonyl compounds is reported using a sub-stoichiometric quantity of an oxoammonium salt bearing the nitrate counterion. The approach proves successful for the oxidation of a range of alcohol substrates including those bearing an oxygen atom β to the site of oxidation or an α-trifluoromethyl moiety. The mechanism of the reaction has been probed and also gives an insight into the previously reported nitric acid mediated oxidation of alcohols.
- Miller, Shelli A.,Sandoval, Arturo León,Leadbeater, Nicholas E.
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supporting information
(2019/12/25)
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- Tuning Flavin-Based Photocatalytic Systems for Application in the Mild Chemoselective Aerobic Oxidation of Benzylic Substrates
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New flavin-based photocatalytic systems used for chemoselective aerobic visible-light oxidations have been developed by tuning the flavin structure and reaction conditions. 1,3-Dimethyl-7-trifluoromethylalloxazine (2) and 10-butyl-3-methyl-7-trifluoromethylisoalloxazine (3) were shown to mediate the selective oxidation of benzyl alcohols to form aldehydes in the presence of Cs2CO3. Flavin 3 was superior in the oxidation of toluene derivatives to form aldehydes in the presence of trifluoroacetic acid. On the other hand, photooxidations provided by ethylene-bridged quaternary flavinium salt 1 gave the corresponding carboxylic acids. The usefulness of the developed catalytic systems using 1–3 was also demonstrated in the oxidation of secondary benzylic and aliphatic alcohols, and benzylic methylene groups to form the corresponding ketones. The systems have the advantage of a broad substrate scope and metal-free conditions, which distinguish them from the previously reported flavin photooxidation reactions.
- Tolba, Amal Hassan,Vávra, Franti?ek,Chudoba, Josef,Cibulka, Radek
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supporting information
p. 1579 - 1585
(2019/12/24)
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- Redox Active Hexanuclear Mixed Valence Dicationic Ce(III)/Ce(IV) Coordination Clusters
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A series of mixed valence hexanuclear dicationic coordination clusters containing two μ4-O2– bridges with general formula M2+(X–)2 [M = CeIV2CeIII4(μ4
- Arumugam, Selvakumar,Mondal, Kartik Chandra,Shankar, Bhaskaran
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supporting information
p. 4127 - 4136
(2020/11/23)
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- Visible-light-induced selective aerobic oxidation of sp3 C-H bonds catalyzed by a heterogeneous AgI/BiVO4 catalyst
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An efficient oxidation of sp3 C-H bonds to esters and ketones has been developed using AgI/BiVO4 as the photocatalyst and O2 as the oxidant in water. Various substrates can be transformed into the desired esters and ketones in moderate to good yields. The synthetic utility of this approach has been demonstrated by gram-level experiments and consecutive oxidation experiments. A plausible mechanism has been proposed.
- Jiang, Li-Ya,Ming, Jing-Jing,Wang, Lian-Yue,Jiang, Yuan-Yuan,Ren, Lan-Hui,Wang, Zi-Cheng,Cheng, Wen-Chen
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supporting information
p. 1156 - 1163
(2020/03/11)
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- A Strategy for Accessing Aldehydes via Palladium-Catalyzed C?O/C?N Bond Cleavage in the Presence of Hydrosilanes
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We report the catalytic reduction of both active esters and amides by selective C(acyl)?X (X=O, N) cleavage to access aldehyde functionality via a palladium-catalyzed strategy. Reactions are promoted by hydrosilanes as reducing reagents with good to excellent yields and with excellent chemoselectivity for C(acyl)?N and C(acyl)?O bond cleavage. Carboxylic acid C(acyl)?O bonds are activated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) to form triazine ester intermediates, which further react with hydrosilanes to yield aldehydes in one-pot two-step procedures. We demonstrate that C(acyl)?O cleavage/formylation offers higher yields and broader substrate scopes compared with C(acyl)?N cleavage under the same reaction conditions.
- He, Zhanyu,Liu, Tingting,Ru, Junxiang,Wang, Yulin,Wang, Zijia,Zeng, Zhuo
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supporting information
p. 5794 - 5800
(2020/12/01)
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- Kinetic and thermodynamic modulation of dynamic imine libraries driven by the hexameric resorcinarene capsule
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The composition of dynamic covalent imine libraries (DCL) adapts to the presence of the hexameric resorcinarene capsule. In the presence of the self-assembled capsule, a kinetic and thermodynamic modulation of the imine constituents of the DCLs was observed, which was induced by an unusual predatory action of the capsule on specific imine constituents. More complex 2 × 2 DCLs also adapt to the presence of the hexameric capsule, showing a thermodynamic and kinetic modulation of the constituents induced by the predatory action of the capsule. By cross-referencing experimental data, a good selectivity (up to 66%) for one constituent can be induced in a 2 × 2 DCL.
- Gambaro, Stefania,Talotta, Carmen,Della Sala, Paolo,Soriente, Annunziata,De Rosa, Margherita,Gaeta, Carmine,Neri, Placido
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p. 14914 - 14923
(2020/10/13)
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- Continuous flow synthesis of aryl aldehydes by Pd-catalyzed formylation of phenol-derived aryl fluorosulfonates using syngas
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This communication describes the palladium-catalyzed reductive carbonylation of aryl fluorosulfonates (ArOSO2F) using syngas as an inexpensive and sustainable source of carbon monoxide and hydrogen. The conversion of phenols to aryl fluorosulfonates can be conveniently achieved by employing the inexpensive commodity chemical sulfuryl fluoride (SO2F2) and base. The developed continuous flow formylation protocol requires relatively low loadings for palladium acetate (1.25 mol%) and ligand (2.5 mol%). Good to excellent yields of aryl aldehydes were obtained within 45 min for substrates containing electron withdrawing substituents, and 2 h for substrates containing electron donating substituents. The optimal reaction conditions were identified as 120 °C temperature and 20 bar pressure in dimethyl sulfoxide (DMSO) as solvent. DMSO was crucial in suppressing Pd black formation and enhancing reaction rate and selectivity. This journal is
- Hanselmann, Paul,Hone, Christopher A.,Hu, Guixian,K?ckinger, Manuel,Kappe, C. Oliver
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p. 22449 - 22453
(2020/07/03)
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- Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
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We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
- Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
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supporting information
(2020/03/25)
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- A chemoselective photolabile protecting group for aldehydes
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A new and high-efficiency photolabile protecting group (PLPG) for aldehydes is described. The PLPG was introduced to aldehydes by using a Lewis acid. Results showed that the PLPG can be released rapidly and smoothly under ultraviolet (UV) irradiation with high efficiency and low cost. This PLPG can easily synthesized and also be selectively protect aldehydes in the presence of ketones.
- Peng, Tao,Wang, Gang,Wang, Lin,Wen, Xiaoxue,Xu, Jing,Xu, Kaijun,Yang, Hongpeng,Zhang, Shouguo
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supporting information
(2020/02/29)
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- Mild environment-friendly oxidative debenzylation of N-benzylanilines using DMSO as an oxidant
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Oxidative debenzylation of N-benzyl aromatic amines using DMSO as a non-toxic oxidant and catalyzed by TsOH gave Nphenylimines, which were spontaneously hydrolyzed to form anilines and benzaldehydes in good yields. This reaction employs mild, metal-free conditions. The conditions are also suitable for the debenzylation of benzylphenylethers.
- Yoshinaga, Tatsuro,Iwata, Takayuki,Shindo, Mitsuru
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supporting information
p. 191 - 194
(2020/02/25)
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- Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent
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The trifluoromethylation of iodoarenes was accomplished by use of a 2-trifluoromethylbenzimidazoline derivative as the trifluoromethylating reagent and a catalytic amount of Cu(I) in the presence of 2,2'-bipyridyl as the ligand. Through a mechanistic study, we found that the oxidative addition of the iodoarene to the Cu(I)–CF3 species is the rate-determining step.
- Akiyama, Takahiko,Ishikawa, Taisuke,Kamiyama, Nanami,Uchikura, Tatsuhiro
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supporting information
p. 2442 - 2447
(2020/11/07)
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- 1,1,1,3,3,3-Hexafluoroisopropanol as an efficient medium for the room temperature oxidation of styrenes to benzaldehydes
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A room temperature N-hydroxyphthalimide-catalyzed oxidation of styrene derivatives to the corresponding aldehydes has been developed. The use of 1,1,1,3,3,3-hexafluoroisopropanol as the solvent was determined as being key for efficient oxidation. The incorporated oxygen atom originates from molecular dioxygen.
- Zhang, Zhuyong,Chen, Weidong,Luo, Junfei
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supporting information
(2020/10/23)
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- Donor-Flexible Bis(pyridylidene amide) Ligands for Highly Efficient Ruthenium-Catalyzed Olefin Oxidation
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An exceptionally efficient ruthenium-based catalyst for olefin oxidation has been designed by exploiting N,N′-bis(pyridylidene)oxalamide (bisPYA) as a donor-flexible ligand. The dynamic donor ability of the bisPYA ligand, imparted by variable zwitterionic and neutral resonance structure contributions, paired with the redox activity of ruthenium provided catalytic activity for Lemieux–Johnson-type oxidative cleavage of olefins to efficiently prepare ketones and aldehydes. The ruthenium bisPYA complex significantly outperforms state-of-the-art systems and displays extraordinary catalytic activity in this oxidation, reaching turnover frequencies of 650 000 h?1 and turnover numbers of several millions.
- Albrecht, Martin,Salzmann, Kevin,Segarra, Candela
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supporting information
p. 8932 - 8936
(2020/04/22)
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- Spinel Structured Copper Ferrite Nano Catalyst with Magnetic Recyclability for Oxidative Decarboxylation of Phenyl Acetic Acids
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Abstract: A simple, efficient and environmentally benign method has been discussed for the synthesis of aldehydes and ketones by the oxidative decarboxylation of phenylacetic acid under ligand free condition using simple, efficient, preparatively easy, magnetically recoverable and low cost spinel CuFe2O4 nanoparticles. The catalyst was characterised using powder-XRD, FTIR, FE-SEM, EDX, VSM and HRTEM. The recyclability was examined and the results showed that the catalyst remained almost equally active up to five consecutive cycles. Graphic Abstract: Spinel Structured Copper Ferrite is a very efficient nano catalyst for Oxidative decarboxylation of Phenyl acetic acids and can be reused up to five cycles without significant loss in catalytic activity.[Figure not available: see fulltext.].
- Rahman, Taskia,Borah, Geetika,Gogoi, Pradip K.
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p. 2267 - 2272
(2020/02/18)
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- Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas
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The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 645 - 656
(2020/05/14)
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- Synthesis and structure activity relationships of cyanopyridone based anti-tuberculosis agents
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Mycobacterium tuberculosis, the causative agent of tuberculosis, relies on thymidylate kinase (MtbTMPK) for the synthesis of thymidine triphosphates and thus also DNA synthesis. Therefore, this enzyme constitutes a potential Achilles heel of the pathogen. Based on a previously reported MtbTMPK 6-aryl-substituted pyridone inhibitor and guided by two co-crystal structures of MtbTMPK with pyridone- and thymine-based inhibitors, we report the synthesis of a series of aryl-shifted cyanopyridone analogues. These compounds generally lacked significant MtbTMPK inhibitory potency, but some analogues did exhibit promising antitubercular activity. Analogue 11i demonstrated a 10-fold increased antitubercular activity (MIC H37Rv, 1.2 μM) compared to literature compound 5. Many analogues with whole-cell antimycobacterial activity were devoid of significant cytotoxicity.
- Boshoff, Helena I. M.,Caljon, Guy,Forbes, He Eun,Hulpia, Fabian,Jian, Yanlin,Munier-Lehmann, Héle?ne,Risseeuw, Martijn D. P.,Van Calenbergh, Serge
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- Combining Flavin Photocatalysis and Organocatalysis: Metal-Free Aerobic Oxidation of Unactivated Benzylic Substrates
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We report a system with ethylene-bridged flavinium salt 2b which catalyzes the aerobic oxidation of toluenes and benzyl alcohols with high oxidation potential (Eox > +2.5 V vs SCE) to give the corresponding benzoic acids under visible light irradiation. This is caused by the high oxidizing power of excited 2b (E(2b?) = +2.67 V vs SCE) involved in photooxidation and by the accompanying dark organocatalytic oxygenation provided by the in situ formed flavin hydroperoxide 2b-OOH.
- Zelenka, Jan,Svobodová, Eva,Tarábek, Ján,Hoskovcová, Irena,Boguschová, Veronika,Bailly, Sarah,Sikorski, Marek,Roithová, Jana,Cibulka, Radek
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supporting information
p. 114 - 119
(2019/01/11)
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- Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
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The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
- Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
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supporting information
p. 6187 - 6193
(2019/11/20)
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- A Simple, Mild and General Oxidation of Alcohols to Aldehydes or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and Oxidant
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A practical, general and mild oxidation of primary and secondary alcohols to carbonyl compounds proceeds in yields of up to 99% using SO2F2 as electrophile in DMSO as both the oxidant and the solvent at ambient temperature. No moisture- and oxygen-free conditions are required. Stoichiometric amount of inexpensive K2CO3, which generates easy to separate by-products, is used as the base. Thus, 5-gram scale runs proceeded in nearly quantitative yields by a simple filtration as the work-up. The use of a polar solvent such as DMSO, which usually promotes competing Pummerer rearrangement, is also noteworthy. This protocol is compatible with a variety of common N-, O-, and S-functional groups on (hetero)arene, alkene and alkyne substrates (68 examples). The protocol was applied (99% yield) to a formal synthesis of the important cholesterol-lowering drug Rosuvastatin. (Figure presented.).
- Zha, Gao-Feng,Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2262 - 2267
(2019/04/17)
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- 3-BocNH-ABNO-catalyzed aerobic oxidation of alcohol at room temperature and atmospheric pressure
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A transition-metal-free catalytic system has been developed for selective transformation of alcohol to aldehydes or ketones. The reactions were performed with 3-(tert-butoxycarbonylamino)-9-azabicyclo[3.3.1]nonane N-oxyl (3-BocNH-ABNO) as the catalyst, NaNO2 as the co-catalyst, molecular oxygen as the terminal oxidant, and AcOH as the solvent under room temperature. This catalytic system exhibited broad functional group tolerance. A series of alcohol substrates, including primary and secondary benzylic alcohols, heteroaromatic analogues, primary and secondary aliphatic alcohols, could be converted into their corresponding aldehydes and ketones in good conversions and selectivities.
- Zhao, Yajing,Li, Yutong,Shen, Zhenlu,Hu, Xinquan,Hu, Baoxiang,Jin,Sun, Nan,Li, Meichao
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supporting information
(2019/08/06)
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- Highly Selective Photocatalytic Valorization of Lignin Model Compounds Using Ultrathin Metal/CdS
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Depolymerization of recalcitrant lignin is a crucial step in realizing the full potential of transforming biomass to value-added small organic molecules. Herein, we report a photocatalytic system consisting of ultrathin CdS nanosheets decorated with first-row transition metals (M/CdS) for the direct photocleavage of lignin model compounds to small aromatic products. In the meantime, the reducing power of M/CdS is utilized to simultaneously generate another valuable product, H2, hence eliminating the necessity of sacrificial reagents and maximizing the energy conversion efficiency. We further demonstrate that, by judiciously modulating the photocatalytic conditions, it is feasible to yield different products with very high selectivity using the same catalyst of Ni/CdS. A series of control experiments were performed to investigate the mechanistic steps of each reaction and highlight the important roles played by both solvent and base in the photocleavage of the β-O-4 bond in lignin valorization.
- Han, Guanqun,Yan, Tao,Zhang, Wei,Zhang, Yi C.,Lee, David Y.,Cao, Zhi,Sun, Yujie
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p. 11341 - 11349
(2019/11/21)
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- Stepwise degradation of hydroxyl compounds to aldehydes: Via successive C-C bond cleavage
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Stepwise degradation of hydroxyl compounds to aldehydes via successive cleavage of C-C bonds was achieved by using a bimetallic catalytic system (PdCl2 + CuCl) without any ligands and additives. The broad applicability is expanded to a diverse range of aromatic, aliphatic, primary and secondary alcohols, as well as lignin model compounds.
- Liu, Mingyang,Zhang, Zhanrong,Shen, Xiaojun,Liu, Huizhen,Zhang, Pei,Chen, Bingfeng,Han, Buxing
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supporting information
p. 925 - 928
(2019/01/24)
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- Dehydrogenative Coupling of Aldehydes with Alcohols Catalyzed by a Nickel Hydride Complex
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A nickel hydride complex, {2,6-(iPr2PO)2C6H3}NiH, has been shown to catalyze the coupling of RCHO and R′OH to yield RCO2R′ and RCH2OH, where the aldehyde also acts as a hydrogen acceptor and the alcohol also serves as the solvent. Functional groups tolerated by this catalytic system include CF3, NO2, Cl, Br, NHCOMe, and NMe2, whereas phenol-containing compounds are not viable substrates or solvents. The dehydrogenative coupling reaction can alternatively be catalyzed by an air-stable nickel chloride complex, {2,6-(iPr2PO)2C6H3}NiCl, in conjunction with NaOMe. Acids in unpurified aldehydes react with the hydride to form nickel carboxylate complexes, which are catalytically inactive. Water, if present in a significant quantity, decreases the catalytic efficiency by forming {2,6-(iPr2PO)2C6H3}NiOH, which causes catalyst degradation. On the other hand, in the presence of a drying agent, {2,6-(iPr2PO)2C6H3}NiOH generated in situ from {2,6-(iPr2PO)2C6H3}NiCl and NaOH can be converted to an alkoxide species, becoming catalytically competent. The proposed catalytic mechanism features aldehyde insertion into the nickel hydride as well as into a nickel alkoxide intermediate, both of which have been experimentally observed. Several mechanistically relevant nickel species including {2,6-(iPr2PO)2C6H3}NiOC(O)Ph, {2,6-(iPr2PO)2C6H3}NiOPh, and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh have been independently synthesized, crystallographically characterized, and tested for the catalytic reaction. While phenol-containing molecules cannot be used as substrates or solvents, both {2,6-(iPr2PO)2C6H3}NiOPh and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh are efficient in catalyzing the dehydrogenative coupling of PhCHO with EtOH.
- Eberhardt, Nathan A.,Wellala, Nadeesha P. N.,Li, Yingze,Krause, Jeanette A.,Guan, Hairong
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p. 1468 - 1478
(2019/04/17)
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- AN IMPROVED PROCESS FOR PREPARATION OF TRIFLUOROMETHYLBENZALDEHYDES AND INTERMEDIATES THEREOF
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The present invention provides an in-situ process for preparation of a compound of formula 1 and intermediate thereof, These compounds are useful chemical intermediates for the production of pesticides and pharmaceutical products.
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Page/Page column 7; 8
(2019/04/10)
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- Ligand-free trifluoromethylation of iodoarenes by use of 2-Aryl-2-trifluoromethylbenzimidazoline as new trifluoromethylating reagent
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N-Methyl 2-aryl-2-trifluoromethylbenzimidazolines were synthesized and utilized in the trifluoromethylation reaction of iodoarenes in the presence of copper(I) salt and base. Iodoarenes bearing electron-donating and electron-withdrawing groups were tolerant to this reaction in the absence of a ligand and gave trifluorotoluene derivatives in good to high yields.
- Miyagawa, Masamichi,Ishikawa, Taisuke,Shinkai, Kota,Akiyama, Takahiko
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supporting information
p. 29 - 31
(2019/01/04)
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- Titania-catalyzed H2O2 thermal oxidation of styrenes to aldehydes
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We investigated the selective oxidation of styrenes to benzaldehydes by using a non-irradiated TiO2–H2O2 catalytic system. The oxidation promotes multi-step reactions from styrenes, including the cleavage of a C=C double bond and the addition of an oxygen atom selectively and stepwise to provide the corresponding benzaldehydes in good yields (up to 72percent). These reaction processes were spectroscopically shown by fluorescent measurements under the presence of competitive scavengers. The absence of the signal from OH radicals indicates the participation of other oxidants such as hydroperoxy radicals (?OOH) and superoxide radicals (?O2?) into the selective oxidation from styrene to benzaldehyde.
- Hong, Dachao,Ino, Daisuke,Ito, Satoru,Kon, Yoshihiro,Konno, Hideo,Nakashima, Takuya,Sato, Kazuhiko
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supporting information
(2019/07/18)
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- Rhenium-Catalyzed Reduction of Carboxylic Acids with Hydrosilanes
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Re2(CO)10 efficiently catalyzes the direct reduction of various carboxylic acids under mild conditions (rt, irradiation 350 or 395 nm). While aliphatic carboxylic acids were readily converted to the corresponding disilylacetals with low catalyst loading (0.5 mol %) in the presence of Et3SiH (2.2 equiv), aromatic analogues required more drastic conditions (Re2(CO)10 5 mol %, Ph2MeSiH 4.0 equiv) to afford the corresponding aldehydes after acid treatment.
- Wei, Duo,Buhaibeh, Ruqaya,Canac, Yves,Sortais, Jean-Baptiste
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supporting information
p. 7713 - 7716
(2019/10/10)
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- Continuous-flow Synthesis of Aryl Aldehydes by Pd-catalyzed Formylation of Aryl Bromides Using Carbon Monoxide and Hydrogen
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A continuous-flow protocol utilizing syngas (CO and H2) was developed for the palladium-catalyzed reductive carbonylation of (hetero)aryl bromides to their corresponding (hetero)aryl aldehydes. The optimization of temperature, pressure, catalyst and ligand loading, and residence time resulted in process-intensified flow conditions for the transformation. In addition, a key benefit of investigating the reaction in flow is the ability to precisely control the CO-to-H2 stoichiometric ratio, which was identified as having a critical influence on yield. The protocol proceeds with low catalyst and ligand loadings: palladium acetate (1 mol % or below) and cataCXium A (3 mol % or below). A variety of (hetero)aryl bromides at a 3 mmol scale were converted to their corresponding (hetero)aryl aldehydes at 12 bar pressure (CO/H2=1:3) and 120 °C reaction temperature within 45 min residence time to afford products mostly in good-to-excellent yields (17 examples). In particular, a successful scale-up was achieved over 415 min operation time for the reductive carbonylation of 2-bromo-6-methoxynaphthalene to synthesize 3.8 g of 6-methoxy-2-naphthaldehyde in 85 % isolated yield. Studies were conducted to understand catalyst decomposition within the reactor by using inductively coupled plasma–mass spectrometry (ICP–MS) analysis. The palladium could easily be recovered using an aqueous nitric acid wash post reaction. Mechanistic aspects and the scope of the transformation are discussed.
- Hone, Christopher A.,Lopatka, Pavol,Munday, Rachel,O'Kearney-McMullan, Anne,Kappe, C. Oliver
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p. 326 - 337
(2018/11/23)
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- Cercosporin-bioinspired selective photooxidation reactions under mild conditions
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The development of an efficient system for selective oxidation of organic compounds to generate more valuable compounds with molecular oxygen is a significant challenge in industrial chemistry. Bioinspired by the ability of naturally occurring perylenequinonoid pigments (PQPs) to generate reactive oxygen species (ROS) upon photoirradiation, here we report that cercosporin, one of the perylenequinonoid pigments, can function as a cost-effective and environmentally friendly photocatalyst for a wide range of selective oxidations, including benzylic C-H bonds to carbonyls, amines to aldehydes, and sulfides to sulfoxides. All of the representative reactions proceeded smoothly with high efficiency under mild conditions. Owing to the use of inexpensive metal-free visible light-driven photocatalyst produced from microbial fermentation with cheap glucose as the starting material and the ease of handling, we expect that this developed method will be particularly attractive for many more applications in synthetic transformation.
- Li, Jia,Bao, Wenhao,Tang, Zhaocheng,Guo, Baodang,Zhang, Shiwei,Liu, Haili,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 6073 - 6081
(2019/11/20)
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- Selective Aerobic Oxidation of Alcohols with NO3? Activated Nitroxyl Radical/Manganese Catalyst System
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A homogeneous Mn(NO3)2/2,2,6,6-tetramethylpiperidin-1-yl)oxyl/2-picolinic acid catalyst system is highly active and versatile for the selective aerobic oxidation of alcohols (2,2,6,6-tetramethylpiperidin-1-yl)oxyl=TEMPO, 2-picolinic acid=PyCOOH). The catalytic method enables near quantitative conversion of various primary alcohols to the respective aldehydes using a very simple reaction setup and workup. This study presents findings on the catalyst stability and mechanisms of deactivation. The results show that NO3? plays a crucial catalytic role in the reaction as a source of oxygen activating NOx species. Yet, disproportionation of NO3? to the volatile NO2 during the reaction leads to catalyst deactivation under open air conditions. Catalyst deactivation through this route can be overcome by adding a catalytic amount of nitrate salt, for example NaNO3 into the reaction. This stabilizes the Mn(NO3)2/TEMPO/PyCOOH catalyst and enables oxidation of various primary alcohols to the respective aldehydes using low catalyst loadings under ambient conditions. Secondary alcohols can be oxidized with a modified catalyst utilizing sterically accessible nitroxyl radical 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO) instead of TEMPO. At the end of the alcohol oxidation, pure carbonyl products and the reusable catalyst can be recovered simply by extracting with organic solvent and dilute aqueous acid, followed by evaporation of both phases.
- Lagerblom, Kalle,Keskiv?li, Juha,Parviainen, Arno,Mannisto, Jere,Repo, Timo
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p. 2908 - 2914
(2018/05/03)
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- Fe(NO3)3/2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ): An efficient catalyst system for selective oxidation of alcohols under aerobic conditions
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A practical and efficient catalyst system for the oxidation of alcohols to carbonyl compounds using catalytic amounts of DDQ and Fe(NO3)3 with air as the environmentally benign oxidant has been developed. A variety of benzylic, heterocyclic, allylic and propargylic alcohols were smoothly converted into aldehydes or ketones in good to excellent yields. In case of large-scale reaction for the oxidation of benzyl alcohol, benzaldehyde was obtained in 93% isolated yield. Moreover, a possible reaction mechanism was proposed.
- Hu, Yongke,Chen, Lei,Li, Bindong
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- A primary or secondary alcohol aqueous phase oxidation method of preparing aldehyde ketone (by machine translation)
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The invention discloses an aqueous phase oxidation of a primary or secondary alcohol preparation can comprise solvents, including: to the DAPGS - 550 - M surfactant in aqueous solution with a primary or secondary alcohol, potassium sulfate, silver nitrate and sulfonic acid bismith trifluoromethanesulfonate, to 400 - 700 rpm stirring 1 - 24 H-, extracted with ethyl acetate after, steaming and, chromatography, to obtain the target product; said DAPGS - 550 - M shown as formula I: So that the primary or secondary alcohol class compounds can be converted into the aldehyde compound. The whole reaction at room temperature, to a very large extent of reaction that has solved the problem of energy consumption. The method is simple, high yield, purity of 98% or more. Mild condition, wide substrate range, is not only simple and a primary or zhongzhong kind compound can be suitable, complex natural product also can be modified by this method. The reaction system can be recycled, the solvent pollution problem. (by machine translation)
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Paragraph 0062-0065
(2018/08/03)
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- Effects of Ancillary Ligands on Redox and Chemical Properties of Ruthenium Coordinated Azoaromatic Pincer
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In this work, the effect of the electronically different ancillary ligands on the overall properties of the RuIIL moiety (L = 2,6-bis(phenylazo)pyridine) in heteroleptic complexes of general formula [RuLQCl]0/+ was investigated. Four different ancillary ligands (Q) with different electronic effects were used to prepare the heteroleptic compounds from the precursor complex, [RuL(CH3CN)Cl2] (1); Q = pcp: 2-(4-chloro-phenylazo)pyridine (strong π-acceptor), [2]+ bpy: 2,2′-bipyridyl (moderate π-acceptor), [3]+ acac-: acetylacetonate (strong σ-donor), 4; and DTBCat2-: 3,5-di-tert-butyl catecholate (strong π-donor), 5. The complexes [2]+, [3]+, 4, and 5 were fully characterized and structurally identified. The electronic structures of these complexes along with their redox partners were elucidated by using a host of physical measurements: nuclear magnetic resonance, cyclic voltammetry, electronic paramagnetic resonance, UV-vis-NIR spectroscopy, and density functional theory. The studies revealed significant effects of the coligands on azo bond lengths of the RuL moiety and their redox behavior. Aerobic alcohol oxidation reactions using these Ru complexes as catalysts were scrutinized. It was found that the catalytic efficiency is primarily controlled by the electronic effect of the coligand. Accordingly, the complex [2]+ (containing a strong π-acceptor coligand, pcp) brings about oxidation efficiently, producing 86% of benzaldehyde. In comparison, however, the complexes 4 and 5 (containing electron donating coligand) furnished only 15-20% of benzaldehyde under identical reaction conditions. Investigations of the reaction mechanism suggest that an unstable Ru-H species is formed, which is transformed to a Ru-hydrazo intermediate by H-walking as reported by Hall et al. (J. Am. Chem. Soc., 2015, 137, 12330). Aerial O2 regenerates the catalyst via oxidation of the hydrazo intermediate.
- Rath, Santi Prasad,Sengupta, Debabrata,Ghosh, Pradip,Bhattacharjee, Rameswar,Chakraborty, Mou,Samanta, Subhas,Datta, Ayan,Goswami, Sreebrata
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p. 11995 - 12009
(2018/09/25)
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