- Substituent and Solvent Effects in the Reactions of Diaryldiazomethanes with 2,3-Dichloro-5,6-dicyanobenzoquinone
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Kinetic studies have been made of the reactions of fifteen meta- and para-substituted diphenyldiazomethanes(DDMs) with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in benzene.The second order rate constants, k, increased with the electron-donability of the substituents, and the value could be correlated with the Yukawa-Tsuno equation: log k/k0 = -2.33(?0 + 0.47Δ+) + 0.017, (r = 0.996, 30 deg C).The ρ value, -2.33, indicates the development of a positive charge at the diazo carbon in the transition state, while the R value, 0.47, confirms the moderate stabilization of the positive charge by the ?-electronic contribution of the para substituents.The rate constants have also been determined for the reaction of diphenyldiazomethane(DDM) with DDQ in 28 aprotic solvents.The effects of solvents can be interpreted in terms of the basicity and the steric nature of the solvents.The products of these reactions were poly(2,3-dichloro-5,6-dicyanohydroquinone benzhydryl ether)s, which were easily convertible into benzophenones and α,α-dimethoxydiphenylmethane, together with 2,3-dichloro,5,6-dicyanohydroquinone, under the influence of water and methanol.These solvolysis products were also obtained in excellent yields in the initial presence of these additives.
- Oshima, Takumi,Nagai, Toshikazu
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- COMPARISON OF PHOTOINDUCED ELECTRON TRANSFER REACTIONS OF AROMATIC CARBONYL VS. CYANO COMPOUNDS WITH ELECTRON DONORS IN CONDENSED PHASE: THE IMPORTANCE OF THE SPIN STATE OF THE GEMINATE ION PAIR FOR OBTAINING HIGH ION YIELDS.
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Photoinduced electron transfer reactions in acetonitrile with benzophenone, anthraquinone, 9-cyanoanthracene and 9,10-dicyanoanthracene as electron acceptors, and with 1,4-diazabicyclooctane and N,N-dimethylaniline as electron donors have been studied with ns-laser flash photolysis and fluorescence quenching measurements.For these systems the resulting free ion yield depends on the spin state of the geminate ion pair: its separation is very efficient if formed in a triplet state (carbonyl compounds/donors), while it is very inefficient if formed in a singlet state (cyanoantracenes/donors).In the triplet systems, geminate back electron transfer is limited by the rate of spin flip.
- Haselbach, Edwin,Vauthey, Eric,Suppan, Paul
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- Oxovanadium(v)-catalyzed deoxygenative homocoupling reaction of alcohols
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Oxovanadium(v)-catalyzed transformation of alcohols in the presence of hydrazine derivatives was demonstrated. The direct hydrazination reaction of 1,3-diphenylprop-2-en-1-ol with 1,1-diphenylhydrazine in the presence of VO(OSiPh3)3 as a catalyst and MS3A as a dehydrating reagent proceeded to afford the corresponding hydrazination product. On the contrary, the utilization of 1,1-dimethylhydrazine instead of 1,1-diphenylhydrazine was found to induce the deoxygenative homocoupling reaction of the allyl alcohol to give the corresponding 1,5-diene as a major product. In addition to the deoxygenative homocoupling product, the allyl amine into which aniline was introduced was also obtained by using 1,2-diphenylhydrazine in the reaction of 1,3-diphenyl-2-methylprop-2-en-1-ol. Oxovanadium(v)-catalyzed deoxygenative homocoupling reaction of benzyl alcohols could also be performed in the presence of 1,1-dimethylhydrazine.
- Sakuramoto, Takashi,Donaka, Yosuke,Tobisu, Mamoru,Moriuchi, Toshiyuki
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- Ligand-free palladium-catalyzed aerobic oxidative coupling of carboxylic anhydrides with arylboronic acids
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We report a new, effective and environmentally friendly protocol for selective aerobic oxidative coupling of arylboronic acids with carboxylic anhydrides in the presence of ligand-free palladium catalyst. The aryl benzoates are obtained in good to excellent yields.
- Yin, Weiyan,He, Haifeng,Zhang, Yani,Long, Tong
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- Co(ii)-cluster-based metal-organic frameworks as efficient heterogeneous catalysts for selective oxidation of arylalkanes
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To explore metal-organic frameworks (MOFs) based on Co-clusters as heterogeneous catalysts to selectively catalyze the reaction of C-H bond oxidation of aromatic alkanes to their corresponding ketones, three MOFs {[Co5(pmbcd)2(μ3-OH)2(H2O)4(DMF)2]·4DMF}n (MOF 1), {[Co2(pmbcd)(bpea)2]·2H2O·2DMF}n (MOF 2), and {[Co2(pmbcd)(dpp)2]·3H2O·2DMF}n (MOF 3) (H4pmbcd = 9,9′-(1,4-phenylenebis(methylene))bis(9H-carbazole-3,6-dicarboxylic acid), bpea = 1,2-bis(4-pyridyl)ethane, dpp = 1,3-di(4-pyridyl)propane) were successfully synthesized and structurally characterized. MOF 1 was constructed from a pentanuclear Co(ii) cluster and exhibited a porous framework with channels of 8 × 10 ?2 along the b axis. MOF 2 was constructed from [Co2(CO2)4] units and presented a porous three-dimensional (3D) framework with channels of 11 × 13 ?2 along the b axis and of 10 × 12 ?2 along the c axis. MOF 3 was a flat two-dimensional (2D) layer based on binuclear Co(ii) units when dpp as an auxiliary ligand was introduced. The Co5-cluster-based MOF 1 exhibited excellent catalytic activity for the direct C-H bond activation of arylalkanes to ketones in H2O under room temperature because of its high density of Lewis acidic sites within the frameworks and suitable channel size to access the catalytic sites. It also presented the spatial confinement effect and catalyzed the reaction with high regioselectivity, forming mono-ketones as the sole products. Easy product separation, simple reaction procedures, and recyclability of these catalysts make the catalytic system attractive. Our work highlights the superiority of the MOF-based materials as heterogeneous catalysts.
- Fan, Yanru,Li, Xiao,Gao, Kuan,Liu, Yu,Meng, Xiangru,Wu, Jie,Hou, Hongwei
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- Oxidation of phenylhydrazones of α-keto esters with hypervalent organoiodine reagents
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α-Ketoacids and ketones can easily be regenerated in high yield from their phenylhydrazones via hydroxy azo compounds upon oxidation with hupervalent iodine reagents.
- Barton, Derek H. R.,Jaszberenyi, Joseph Cs.,Shinada, Tetsuro
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- Ionic liquid [bmim]Br assisted chemoselective benzylic [Formula presented] oxidations using tert-butyl hydroperoxide
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A mild and efficient, ionic-liquid-assisted green protocol for the chemoselective oxygenation of benzylic C-H bonds to corresponding ketones using ionic liquid [bmim]Br with tert-butyl hydroperoxide has been developed. The method reported in this paper has the advantages of [bmim]Br acting as recyclable solvent and reagent. The usage of additives such as acids or bases and metal salts is not required. The developed strategy is further extended to oxidation of secondary alcohols to respective ketones under similar optimized reaction conditions.
- Naidu, Shivaji,Reddy, Sabbasani Rajasekhara
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- Mechanism of thermal decomposition of diphenyldiazomethane in the presence of oxygen
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The kinetics, products, and mechanism of thermal decomposition of diphenyldiazomethane (RN2, R = Ph2C) in the presence of oxygen were studied. Thermolysis is accompanied by chemiluminescence. An-emitter of chemiluminescence (3RO) forms in the reaction of benzophenone 0-oxide ROO with RN2.
- Komissarov,Nazarov,Yamilova
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- Thiol ester-boronic acid cross-coupling. Catalysis using alkylative activation of the palladium thiolate intermediate
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(matrix presented) Thiol esters and boronic acids do not participate in cross-coupling in the presence of palladium catalysts. However, efficient palladium-catalyzed thiol ester-boronic acid cross-coupling is observed when simple alkylating agents are present. Alkylative conversion of the very stable palladium-thiolate bond to a labile palladium-thioether bond is presumed to be crucial to the catalysis. Of the systems studied, 4-halo-n-butyl thiol esters were most effective in this cross-coupling.
- Savarin, Cecile,Srogl, Jiri,Liebeskind, Lanny S.
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- Kinetics, products, and mechanism of the reaction of diphenylcarbonyl oxide with sulfoxides
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The kinetics of the reactions of diphenylcarbonyl oxide with dimethyl, di-n-hexyl, diphenyl, dibenzyl, and n-hexylbenzyl sulfoxides in acetonitrile was studied by flash photolysis at 295 K. The oxidation of sulfoxide affords the corresponding sulfone as t
- Nazarov,Chainikova,Krupin,Khursan,Kalinichenko,Komissarov
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- Product selectivity in semiconductor-mediated dehydrazonation of benzophenone hydrazone
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Product selectivity in the dehydrazonation of benzophenone hydrazone by photocatalytic oxidation with various semiconductor photocatalysts has been investigated using ultraviolet-A light. TiO2-P25 shows greater product selectivity of benzophenone formation with 93.9% conversion. Doping of metals on TiO2 selectively enhances the formation of azine from hydrazone. Solvents such as dichloromethane, chloroform, and dichloroethane also enhance the formation of azine.
- Krishnakumar,Selvam,Swaminathan
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- Solid phase synthesis of α-acylamino-α,α-disubstituted ketones
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α-Acylamino-α,α-disubstituted ketones are of interest as ecdysone agonists. Solid phase synthesis of prototypical α-acylamino-α,α-disubstituted ketones on two different solid supports is described. In both cases the ketone was formed by reaction of a Grignard reagent with an N-acyl-α,α-disubstituted amino acid immobilized through its carboxylate as a Weinreb amide derivative.
- Tice, Colin M.,Michelotti, Enrique L.,Mata, Ernesto G.,Nicolàs, Ernesto,Garcia, Javier,Albericio, Fernando
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- Heteropolytungstic acids incorporated in an ordered mesoporous zirconia framework as efficient oxidation catalysts
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Ordered mesoporous composite catalysts consisting of nanocrystalline tetragonal ZrO2 and heteropolytungstic clusters, i.e. 12-phosphotungstic (PTA) and 12-silicotungstic (STA) acids, were prepared via a surfactant-assisted co-polymerization route. According to the X-ray diffraction, transmission electron microscopy and N2 physisorption measurements, the resultant materials possess a well-defined mesoscopic order ranging from wormhole to hexagonal pore structure and exhibit large internal surface area (126-229 m2 g-1) and quite narrow pore size distribution (ca. 2.2-2.6 nm in diameter). Energy dispersive X-ray microanalysis and infrared spectroscopy confirms that the heteropoly clusters are well dispersed within the zirconia matrix, while preserving intact their Keggin structure. The inclusion of PTA and STA clusters in the mesoporous framework has a beneficial effect on the catalytic activity of these materials. Although zirconium oxide and heteropoly acids alone show little catalytic activity, the ZrO 2-PTA and ZrO2-STA heterostructures exhibit surprisingly high activity in hydrogen peroxide mediated oxidation of 1,1-diphenyl-2- methylpropene under mild conditions. Indeed, the mesoporous ZrO2-STA composite sample loaded with 5 wt% STA shows a conversion rate that is 17 times higher than the mesoporous ZrO2. The catalytic activity of these materials is related to the spatial distribution of heteropoly acids in zirconia matrix and possible synergistic interactions between the incorporated Keggin units and Zr(iv) oxohydroxide species.
- Skliri, Euaggelia,Lykakis, Ioannis N.,Armatas, Gerasimos S.
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- A simple synthesis of symmetrical α-diones from organometallic reagents and 1,4-dimethyl-piperazine-2,3-dione
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Short reflux of an equimolar mixture of N-N′-dimethyl ethylenediamine and diethyl oxalate in ipropanol or diethyl ether leads to 1,4-dimethyl-piperazine-2,3-dione, which is able to react with two equivalent of organolithium or Grignard compounds to form symmetrically substituted α-diones in excellent yields.
- Mueller-Westerhoff, Ulrich T.,Zhou, Ming
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- Use of Isopropyl Alcohol as a Reductant for Catalytic Dehydoxylative Dimerization of Benzylic Alcohols Utilizing Ti?O Bond Photohomolysis
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Photohomolysis of Ti?O bonds is utilized in photocatalytic generation of titanium(III) species for dehydroxylative dimerization of benzylic alcohols under UV-light irradiation by using isopropyl alcohol (IPA) as a stoichiometric reductant. In this reaction, IPA works not as a single-electron donor as in the photo-redox catalyzed reactions but as an H-atom-donor. The reaction also proceeds under visible-light irradiation in the presence of thioglycolic acid as a ligand.
- Iwasawa, Nobuharu,Sumiyama, Keiichi,Toriumi, Naoyuki
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- TWO INTERMEDIATES OBSERVED IN THE GRIGNARD REACTION WITH BENZOPHENONE
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Intermediates in the reaction of Grignard reagent with benzophenone in THF were investigated by both ESR and stopped-flow techniques.The short-lived (blue colored) and other long-lived (pink colored radical) intermediates were observed.The pink colored radical intermediate could be in a state of dimeric aggregate of benzophenone anion radicals ion-paired with Grignard cation + in solution.
- Maruyama, Kazuhiro,Hayami, Jun-ichi,Katagiri, Toshimasa
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- Phosphine-free NiBr2-catalyzed synthesis of unsymmetrical diaryl ketones via carbonylative cross-coupling of aryl iodides with Ph3SnX (X = Cl, OEt)
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Abstract The convenient nickel-catalyzed carbonylative coupling of aryl iodides with Ph3SnCl or Ph3SnOEt for synthesis of unsymmetrical diaryl ketones under phosphine-free condition is reported. The reaction occurs efficiently in the presence of Cr(CO)6 as an easy handling solid source of carbon monoxide at atmospheric pressure and 100 °C in DMF under air to deliver the desired ketones in high yield.
- Iranpoor, Nasser,Firouzabadi, Habib,Etemadi-Davan, Elham
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- Oxidation of Benzylic Methylene Compounds to Ketones with 4-Aminoperoxybenzoic Acid Supported on Silica Gel in Presence of Oxygen or Air
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4-Aminoperoxybenzoic acid supported on silica gel in presence of oxygen or air was found to be a convenient and selective oxidant for the oxidation of benzylic methylene compounds to the corresponding ketones.
- Hashemi, Mohammed M.,Ghazanfari, Dadkhoda,Karimi-Jaberi, Zahed
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- Benzimidazole-based palladium-N-heterocyclic carbene: A useful catalyst for C-C cross-coupling reaction at ambient condition
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A convenient way for the synthesis of benzimidazole-based Pd-N-heterocyclic carbene complex and its structural characterization are described. The complex efficiently catalyzes Suzuki cross-coupling reaction in a wide variety of substrates including heteroaromatic system at ambient condition. The catalyst is also effective for multi Suzuki cross-coupling reaction. In addition, the catalyst is equally active toward C-C cross-coupling reaction between acid chloride and arylboronic acid, giving the desired ketones in high yield.
- Gupta, Sumanta,Basu, Basudeb,Das, Sajal
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- A Tale of Copper Coordination Frameworks: Controlled Single-Crystal-to-Single-Crystal Transformations and Their Catalytic C-H Bond Activation Properties
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Metal-organic frameworks (MOFs), as a class of microporous materials with well-defined channels and rich functionalities, hold great promise for various applications. Yet the formation and crystallization processes of various MOFs with distinct topology, connectivity, and properties remain largely unclear, and the control of such processes is rather challenging. Starting from a 0D Cu coordination polyhedron, MOP-1, we successfully unfolded it to give a new 1D-MOF by a single-crystal-to-single-crystal (SCSC) transformation process at room temperature as confirmed by SXRD. We also monitored the continuous transformation states by FTIR and PXRD. Cu MOFs with 2D and 3D networks were also obtained from this 1D-MOF by SCSC transformations. Furthermore, Cu MOFs with 0D, 1D, and 3D networks, MOP-1, 1D-MOF, and HKUST-1, show unique performances in the kinetics of the C-H bond catalytic oxidation reaction.
- Chen, Yifa,Feng, Xiao,Huang, Xianqiang,Lin, Zhengguo,Pei, Xiaokun,Li, Siqing,Li, Jikun,Wang, Shan,Li, Rui,Wang, Bo
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- Electron Transfer Catalyzed Reactions. Electrochemical Induction of the Hydrogen Atom Transfer Oxidation of Alcohols and Other Substrates by Aromatic Halides
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The reduction of aryl halides in the presence of primary or secondary alcohols in liquid ammonia or in pure alcohol leads to the formation of the corresponding carbonyl compounds along an elctrocatalytic process consuming a vanishingly small amount of electricity.The aryl radical generated upon electrochemical reductive cleavage of the aryl halide first abstracts a H atom from the alcohol leading to an hydroxyalkyl radical which deprotonates into the ketyl anion radical, which is itself oxidized into the carbonyl compound.Side reactions are the reduction of the aryl radical and of the hydroxyalkyl radical.A detailed study of the feasibility and the mechanism of the reacton has been carried out by cyclic voltammetry and preparative scale electrolysis.The results underscore the fact that besides its acid-base properties, the H-atom donation ability of the solvent can play an important role in the course of electrochemical reactions.The electron stoichiometry, varying between 0 and 2, and the product distribution are functions of the redox and acid-base properties of the radical resulting from H-atom abstraction and of the redox and cleavage characteristic of the aryl halide anion radical.The reaction allows the oxidation of a large variety of substrates under electrochemically reducing conditions, those which lead to the formation of the aryl radical from the starting aryl halide.
- Andrieux, Claude P.,Badoz-Lambling, Jeanine,Combellas, Catherine,Lacombe, Daniel,Saveant, Jean-Michel,et al.
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- Fabrication of CuCr2O4 spinel nanoparticles: A potential catalyst for the selective oxidation of cycloalkanes via activation of Csp3-H bond
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We report here preparation of CuCr2O4 spinel nanoparticle catalyst, mediated by cationic surfactant CTAB in hydrothermal route. XRD revealed the formation of CuCr2O4 spinel phase and TEM showed the particle size of 30-60 nm. The catalyst was speculated to be highly active for selective oxidation of cyclohexane to cyclohexanone with H2O2. A cyclohexane conversion of 70% with 85% cyclohexanone selectivity was achieved over this catalyst at 50 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 8 reuses and proved its efficacy in the oxidation of other cycloalkanes also.
- Acharyya, Shankha S.,Ghosh, Shilpi,Adak, Shubhadeep,Tripathi, Deependra,Bal, Rajaram
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- Fe3O4@dopa (dopa = dopamine hydrochloride) functionalized Mn(III) Schiff base complex: A promising magnetically separable heterogeneous catalyst for oxidative transformations
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A chiral Schiff base complex has been prepared by treating (R)-1,2-diaminopropane with 3,5-dichlorosalicylaldehyde in ethanol, followed by addition of manganese chloride hexahydrate to generate a homogeneous catalyst, [MnL(Cl)(H2O)] (HMN). Crystal structure of the complex reveals its mononuclear nature. Circular dichroism (CD) studies indicate that the ligand and its corresponding complex contain an asymmetric center. The catalytic activity of HMN toward epoxidation of alkenes, oxidation of alcohols and oxidation of alkanes has been investigated in the presence of iodosylbenzenediacetate (PhI(OAc)2), in acetonitrile. In the present work we found yields to be much higher compared to our previous approaches. For further adaptation, we attached our efficient homogeneous catalyst with surface modified magnetic nanoparticles (Fe3O4@dopa) and thereby obtained a new magnetically separable nanocatalyst Fe3O4@dopa@MnLCl (FDM). This catalyst has been characterized and its oxidation ability assessed in similar conditions as those used for the homogeneous catalyst. Enantiomeric excess in epoxide yield reveals retention of chirality of the active site of Fe3O4@dopa@MnLCl. The catalyst can be recovered by magnetic separation and recycled several times without significant loss of catalytic activity.
- Chakraborty, Aratrika,Chattopadhyay, Tanmay
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- Bioinspired oxidation of oximes to nitric oxide with dioxygen by a nonheme iron(II) complex
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The ability of two iron(II) complexes, [(TpPh2)FeII(benzilate)] (1) and [(TpPh2)(FeII)2(NPP)3] (2) (TpPh2 = hydrotris(3,5-diphenylpyrazol-1-yl)borate, NPP-H = α-isonitrosopropiophenone), of a monoanionic facial N3 ligand in the O2-dependent oxidation of oximes is reported. The mononuclear complex 1 reacts with dioxygen to decarboxylate the iron-coordinated benzilate. The oximate-bridged dinuclear complex (2), which contains a high-spin (TpPh2)FeII unit and a low-spin iron(II)–oximate unit, activates dioxygen at the high-spin iron(II) center. Both the complexes exhibit the oxidative transformation of oximes to the corresponding carbonyl compounds with the incorporation of one oxygen atom from dioxygen. In the oxidation process, the oxime units are converted to nitric oxide (NO) or nitroxyl (HNO). The iron(II)–benzilate complex (1) reacts with oximes to afford HNO, whereas the iron(II)–oximate complex (2) generates NO. The results described here suggest that the oxidative transformation of oximes to NO/HNO follows different pathways depending upon the nature of co-ligand/reductant.
- Bhattacharya, Shrabanti,Lakshman, Triloke Ranjan,Sutradhar, Subhankar,Tiwari, Chandan Kumar,Paine, Tapan Kanti
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- Sonovoltammetric measurement of the rates of electrode processes with fast coupled homogeneous kinetics: Making macroelectrodes behave like microelectrodes
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Voltammetric measurements of the rates of fast homogeneous chemical reactions coupled to heterogeneous electron transfer at macroelectrodes are demonstrated for two systems, the reductive dehalogenations of ortho-bromonitrobenzene and of 3-bromobenzophenone, by the use of power ultrasound to confer fast mass-transport properties so giving the electrodes the kinetic timescale of microelectrodes.
- Compton, Richard G.,Marken, Frank,Rebbitt, Thomas O.
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- Azolium/Hydroquinone Organo-Radical Co-Catalysis: Aerobic C?C-Bond Cleavage in Ketones
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Organo-radical catalysts have recently attracted great interest, and the development of this field can be expected to broaden the applications of organocatalysis. Herein, the first example of a radical-generating system is reported that does not require any photoirradiation, radical initiators, or preactivated substrates. The oxidative C?C-bond cleavage of 2-substituted cyclohexanones was achieved using an azolium salt and a hydroquinone as co-catalysts. A catalytic mechanism was proposed based on the results of diffusion-ordered spectroscopy and cyclic voltammetry measurements, as well as computational studies.
- Nakatsuji, Yuya,Kobayashi, Yusuke,Masuda, Sakyo,Takemoto, Yoshiji
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- RADICAL CATION INTERMEDIATES IN THE FORMATION OF SCHIFF BASES ON IRRADIATED SEMICONDUCTOR POWDERS
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Photocatalytic oxidation of several primary aliphatic amines on irradiated TiO2 powders suspended in anhydrous acetonitrile led to good yields of the corresponding symmetrical N-alkylidene amines.Mechanistic electrochemical investigation of the reaction revealed intermediate formation of an immonium cation in an ECE route.This species is generated via electrooxidation of an α-amino radical formed by deprotonation of the primary oxidation product, an aminium cation radical.The influence of the metal oxide surface on radical cation reactivity is discussed.
- Fox, Marye Anne,Younathan, Janet N.
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- Rh-catalyzed carbonylation of arylzinc compounds yielding symmetrical diaryl ketones by the assistance of oxidizing agents
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Carbonylative homocoupling of arylzinc compounds 1 using 1 atm of CO and 1,2-dibromoethane as an oxidant was achieved in the presence of Rh-dppf catalyst, affording symmetrical diaryl ketones in good yields. Under similar conditions, Pd or Ni catalysts induced oxidative homocoupling of 1 to yield biaryls instead. The beneficial catalysis by Rh in the carbonylation was presumed to stem from the facility by which the migration of the aryl ligand to CO at the Rh3+ intermediate occurred.
- Kobayashi, Kana,Nishimura, Yugo,Gao, Fuxing,Gotoh, Kazuma,Nishihara, Yasushi,Takagi, Kentaro
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- Liquid phase oxidation of diphenylmethane to benzophenone with molecular oxygen over nano-sized Co-Mn catalyst supported on calcined Cow bone
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A well-dispersed Co-Mn catalyst immobilized on calcined Cow bone was synthesized and used, for the first time for the selective synthesis of benzophenone by liquid phase oxidation of diphenylmethane under various reaction conditions. The catalyst was characterized using techniques such as UV-vis, SEM, TEM and BET. The catalyst has shown an excellent activity (87%), selectivity to diphenyl ketone (90%) and stability under solvent free conditions. To investigate the leaching of the metals from the support, results of the original and reusable catalyst was correlated and compared, and the catalytic activity of washed catalyst was also demonstrated. Based on the all catalytic results for this reaction, the new catalyst was found to be a highly active and environmentally friendly solid catalyst and has superior catalytic activity.
- Monjezi,Yazdani,Mokfi,Ghiaci
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- Chloro-ruthenium complexes with carbonyl and N-(aryl)pyridine-2-aldimines as ancillary ligands. Synthesis, characterization and catalytic application in C-C cross-coupling of arylaldehydes with arylboronic acids
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Reaction of N-(aryl)pyridine-2-aldimines (L-R, R = OCH3, CH 3, H, Cl and NO2) with [Ru(CO)2Cl 2]n in refluxing ethanol affords a group of complexes of type [Ru(L-R)(CO)2Cl2]. In these complexes the diimine ligands (L-R) are coordinated to the metal center as NN-donors forming five-membered chelate rings, the carbonyls are mutually cis and the two chlorides are trans. Crystal structure of [Ru(L-OCH3)(CO) 2Cl2] has been determined. All the complexes show characteristic 1H NMR signals, and in dichloromethane solution they display intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows an irreversible oxidation of the metal center within 1.15-1.23 V vs SCE, and reduction(s) of the diimine ligand within -0.70 to -0.96 V vs SCE. The [Ru(L-R)(CO)2Cl2] complexes efficiently catalyze cross-coupling of arylaldehydes with arylboronic acids yielding diaryl ketones.
- Dey, Bikash Kali,Dutta, Jayita,Drew, Michael G.B.,Bhattacharya, Samaresh
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- Clean and efficient benzylic C-H oxidation using a microflow system
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An efficient procedure using microreactors for the oxidation of benzylic compounds is described. This new method is facile, economical, and environmentally friendly. By using microreactors, this oxidation can be accomplished with good yields within 10s at room temperature. Copyright
- Lv, Xiao-Ming,Kong, Ling-Jie,Lin, Qi,Liu, Xiao-Feng,Zhou, Ya-Ming,Jia, Yu
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- Reactions in Dry Media: Oxidative Cleavage of Olefins Adsorbed on Inorganic Supports with Oxygen
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Substituted phenylethylenes adsorbed on inorganic supports are oxidatively cleaved to ketones or aldehydes under illumination in the presence of oxygen.It is suggested that these oxidations invove the intermediacy of cation radicals whose formation is initiated by contact charge-transfer interactions between the olefins on the adsorbing phase and oxygen molecules.
- Aronovitch, Chaim,Mazur, Yehuda
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- Alkyl Hydroperoxide Oxidation of Alkanes and Alkenes with a Highly Active Mn Catalyst
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The system ROOH/(ClO4)4 hydroxylates alkanes and converts ArCR=CH2 to ArCR=O with extremely high activity and good conversions and yields.
- Sarneski, Joseph E.,Michos, Demetrius,Thorp, H. Holden,Didiuk, Mary,Poon, Thomas,et al.
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- Deuterium kinetic isotope effects in homogeneous decatungstate catalyzed photooxygenation of 1,1-diphenylethane and 9-methyl-9H-fluorene: Evidence for a hydrogen abstraction mechanism
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The homogeneous decatungstate W10O324- catalyzed photooxygenation of 1,1-diphenylethane and 9-methyl-9H-fluorene has been studied mechanistically. The primary and β-secondary kinetic isotope effects provide strong evidence for a stepwise mechanism, with a hydrogen atom abstraction in the rate-determining step.
- Lykakis, Ioannis N.,Orfanopoulos, Michael
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- Structural Effects of Olefins in the Photooxygenation with Electron-Accepting Sensitizers. Kinetic Approach to Reactive Intermediates
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Pulsed laser excitation studies on the reactive species in 9-cyanoanthracene(CNA)-sensitized oxygenation of 1,1-diphenyl-2-methylpropene (1a) and (E)-2,3-diphenyl-2-butene (1b) show that the reaction course is mostly governed by competitive quenching of the CNA excited singlet by 1 and oxygen to produce 1+. and 1O2, respectively.The results indicate that the reaction courses of tetraphenylethylene and 2,3-dimethyl-2-butene, for example, can be explaind by exclusive quenching of sensitizer singlets by the olefin and oxygen, respectively.
- Konuma, Satoshi,Aihara, Shin,Kuriyama, Yasunao,Misawa, Hiroaki,Akaba, Ryoichi,et al.
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- Chromium-Mediated Benzylic Oxidations by Sodium Percarbonate in the Presence of a Phase Transfer Catalyst.
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In the presence of catalytic amounts of (n-Bu3SnO)2CrO2, Adogen 464 and p-toluenesulfonic acid, benzylic methylene groups are effectively oxidized into alcohols and ketones by sodium percarbonate in refluxing acetonitrile.
- Muzart, Jacques,Aiet-Mohand, Samia
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- HCl-Catalyzed Aerobic Oxidation of Alkylarenes to Carbonyls
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The construction of C?O bonds through C?H bond functionalization remains fundamentally challenging. Here, a practical chlorine radical-mediated aerobic oxidation of alkylarenes to carbonyls was developed. This protocol employed commercially available HCl as a hydrogen atom transfer (HAT) reagent and air as a sustainable oxidant. In addition, this process exhibited excellent functional group tolerance and a broad substrate scope without the requirement for external metal and oxidants. The mechanistic hypothesis was supported by radical trapping, 18O labeling, and control experiments.
- Niu, Kaikai,Shi, Xiaodi,Ding, Ling,Liu, Yuxiu,Song, Hongjian,Wang, Qingmin
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- Mechanochemical Solvent-Free Suzuki–Miyaura Cross-Coupling of Amides via Highly Chemoselective N?C Cleavage
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Although cross-coupling reactions of amides by selective N?C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challe
- Ma, Yangmin,Shao, Lei,Szostak, Michal,Wang, Ruihong,Zhang, Jin,Zhang, Pei
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supporting information
(2022/01/04)
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- Radical Alkene-Trifluoromethylation-Triggered Nitrile Insertion/Remote Functionalization Relay Processes: Diverse Synthesis of Trifluoromethylated Azaheterocycles Enabled by Copper Catalysis
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A copper-catalyzed alkene-trifluoromethylation-triggered nitrile insertion/remote functionalization relay process has been achieved, in which "interrupted"remote 1,n-difunctionalizations of alkenes with nitrile insertion can deliver iminyl radical interme
- Li, Wen-Cheng,Liao, Wei-Wei,Sun, Yun-Hai,Wei, Zhong-Lin,Wu, Yu-Heng,Xi, Ji-Ming
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supporting information
p. 1110 - 1115
(2022/02/10)
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- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
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We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
- Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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p. 2868 - 2874
(2021/01/21)
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- Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
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The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
- Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
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p. 10455 - 10466
(2021/07/31)
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- NaOTs-promoted transition metal-free C-N bond cleavage to form C-X (X = N, O, S) bonds
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Multifunctional transformation of amide C-N bond cleavage is reported. The protocol applies to benzamide, thioamide, alcohols, and mercaptan under similar reaction conditions catalyzed by NaOTs. It is noteworthy that NaOTs can not only be recycled and reused for up to three cycles without significant loss in catalytic activity, but also catalyze gram-grade reactions. This study provides a novel solution with mild conditions and a simple procedure for transformation of multiple amides.
- Chen, Wei,Liu, Sicheng,Liu, Tingting,Majeed, Irfan,Ye, Xiaojing,Zeng, Zhuo,Zhang, Yuqi,Zhu, Yulin
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p. 8566 - 8571
(2021/10/20)
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- An efficient and practical aerobic oxidation of benzylic methylenes by recyclable: N -hydroxyimide
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An efficient and practical benzylic aerobic oxidation catalyzed by cheap and simple N-hydroxyimide organocatalyst has been achieved with high yields and broad substrate scope. The organocatalyst used can be recycled and reused by simple workup and only minute amount (1 mol% in most cases) of simple iron salt is used as promoter. Phenyl substrates with mild and strong electron-withdrawing group could also be oxygenated in high yields as well as other benzylic methylenes. Influence of substituents, gram-scale application, catalysts decay and general mechanism of this methodology has also been discussed. This journal is
- Wang, Jian,Zhang, Cheng,Ye, Xiao-Qing,Du, Wenting,Zeng, Shenxin,Xu, Jian-Hong,Yin, Hong
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p. 3003 - 3011
(2021/01/28)
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- Gold complexes of bis-indazole-derived N-Heterocyclic carbene: Synthesis, structural characterizations, and catalysis
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A novel series of bis Indy-NHC gold complexes have been developed and investigated via a mild Ag-carbene transfer route. The obtained complexes were characterized by NMR spectroscopy and X-ray diffraction analysis. The catalytic property of these gold complexes was further evaluated in the oxidation of benzylic. The gold complex E1 showed a high catalytic activity in the oxidation of various benzylic substrates, resulting in the corresponding carbonyl compounds with excellent yields using TBHP as oxidant.
- Zhang, Hua,Xu, Ting,Li, Dongdong,Cheng, Tao,Chen, Jing,Zhou, Yang
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- Photo-tunable oxidation of toluene and its derivatives catalyzed by TBATB
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In this report, tetrabutylammonium tribromide (TBATB) was introduced as an efficient visible light active catalyst to carry out the aerobic oxidation of toluene, its derivatives, and some of methyl arenes to benzaldehydes, benzoic acids and ketones in good to high yields. All the oxidation reactions were performed under mild conditions using oxygen as a green oxidant, a catalytic amount of TBATB under blue (460 nm), royal blue (430 nm), and violet LED (400 nm) irradiation. It was found that the reactions selectivity was significantly affected by changing the solvent (from CH3CN to EtOAc) and LED wavelength (from blue to violet). In the following, our mechanistic studies revealed that the visible light oxidation of toluenes and methyl arenes over TBATB could be following a benzyl peroxy radical intermediate.
- Mardani, Atefeh,Kazemi, Foad,Kaboudin, Babak
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- Method for synthesizing acetophenone or benzoic acid compound by oxidizing toluene compound
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The invention provides a method for synthesizing an acetophenone or benzoic acid compound through oxidation of a toluene compound, and belongs to the field of organic synthesis. The method for synthesizing the acetophenone or benzoic acid compound through oxidation of the toluene compound comprises the following step of: under the action of a reaction catalyst and an initiator, illuminating the toluene compound in an oxygen-containing atmosphere in a solvent to obtain the acetophenone compound or the benzoic acid compound, wherein the reaction catalyst is lanthanide series rare earth metal salt, and the initiator is a C1-C6 alcohol compound. The method has the advantages of abundant and easily available substrate sources, mild reaction conditions, good compatibility of substrate functional groups, simple operation, high reaction safety, low cost and the like.
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Paragraph 0046-0052
(2021/05/12)
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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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- Efficient Aliphatic C-H Oxidation and C═C Epoxidation Catalyzed by Porous Organic Polymer-Supported Single-Site Manganese Catalysts
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Bioinspired manganese complexes have emerged over recent decades as attractive catalysts for a number of selective oxidation reactions. However, these catalysts still suffer from oxidative degradation. In the present study, we prepared a series of porous Mn-N4 catalysts in which the catalytic units are embedded in the skeleton of porous organic polymers (POPs). These POP-based manganese catalysts demonstrated high reactivity in the oxidation of aliphatic C-H bonds and the asymmetric epoxidation of olefins. Furthermore, these catalysts could be readily recycled and reused due to their heterogeneous nature. Morphological characterization revealed that the Mn-N4 complex was individually distributed over a porous polymer network. Remarkably, the nature of the single-site catalyst prevented oxidative degradation during the reaction. The present work has thus developed a successful approach for bioinspired single-site manganese catalysts in which the oxidation reaction is confined to a specific channel in an enzyme-like mode.
- Wang, Bingyang,Lin, Jin,Sun, Qiangsheng,Xia, Chungu,Sun, Wei
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p. 10964 - 10973
(2021/09/08)
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- V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
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The versatile application of different functional groups such as alcohols (1° and 2°), alkyl arenes, and (aryl)olefins to construct carbon-oxygen bond via oxidation is an area of intense research. Here, we report a reusable heterogeneous V2O5@TiO2 catalyzed selective oxidation of various functionalities utilizing different mild and eco-compatible oxidants under greener reaction conditions. The method was successfully applied for the alcohol oxidation, oxidative scission of styrenes, and benzylic C?H oxidation to their corresponding aldehydes and ketones. The utilization of mild and eco-friendly oxidizing reagents such as K2S2O8, H2O2 (30 % aq.), TBHP (70 % aq.), broad substrate scope, gram-scale synthesis, and catalyst recyclability are notable features of the developed protocol.
- Upadhyay, Rahul,Kumar, Shashi,Maurya, Sushil K.
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p. 3594 - 3600
(2021/07/02)
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- Visible-light photocatalytic selective oxidation of C(sp3)-H bonds by anion-cation dual-metal-site nanoscale localized carbon nitride
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Selective oxidation of C(sp3)-H bonds to carbonyl groups by abstracting H with a photoinduced highly active oxygen radical is an effective method used to give high value products. Here, we report a heterogeneous photocatalytic alkanes C-H bonds oxidation method under the irradiation of visible light (λ= 425 nm) at ambient temperature using an anion-cation dual-metal-site modulated carbon nitride. The optimized cation (C) of Fe3+or Ni2+, with an anion (A) of phosphotungstate (PW123?) constitutes the nanoscale dual-metal-site (DMS). With a Fe-PW12dual-metal-site as a model (FePW), we demonstrate a A-C DMS nanoscale localized carbon nitride (A-C/g-C3N4) exhibiting a highly enhanced photocatalytic activity with a high product yield (86% conversion), selectivity (up to 99%), and a wide functional group tolerance (52 examples). The carbon nitride performs the roles of both the visible light response, and improves the selectivity for the oxidation of C(sp3)-H bonds to carbonyl groups, along with the function of A-C DMS in promoting product yield. Mechanistic studies indicate that this reaction follows a radical pathway catalyzed by a photogenerated electron and hole on A-C/g-C3N4that is mediated by thetBuO˙ andtBuOO˙ radicals. Notably, a 10 g scale reaction was successfully achieved for alkane photocatalytic oxidation to the corresponding product with a good yield (80% conversion), and high selectivity (95%) under natural sunlight at ambient temperature. In addition, this A-C/g-C3N4photocatalyst is highly robust and can be reused at least six times and the activity is maintained.
- Duan, Limei,Li, Peihe,Li, Wanfei,Liu, Jinghai,Liu, Ying,Liu, Zhifei,Lu, Ye,Sarina, Sarina,Wang, Jinghui,Wang, Yin,Wang, Yingying,Zhu, Huaiyong
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p. 4429 - 4438
(2021/07/12)
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- Selective Oxidation of Benzylic sp3C-H Bonds using Molecular Oxygen in a Continuous-Flow Microreactor
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Selective aerobic oxidation of benzylic sp3 C-H bonds to generate the corresponding ketones was achieved under continuous-flow conditions. The catalysts N-hydroxyphthalimide (NHPI) and tert-butyl nitrite (TBN) as the precursor of the radical under aerobic conditions motivated this process. Flow microreactors operating under optimized conditions enabled this oxidation with higher efficiency and a shortened reaction time of 54 s (total time was 10 min), which was improved 466 times compared with the batch parallel reaction (7.0 h). Notably, the catalyst and solvent recycling (92.6 and 94.5%) and scale-up experiments (0.87 g h-1 in 28 h) demonstrated the practicability of the protocol. The high product selectivity and functional group tolerance of the process allowed the production of ketones in yields of 41.2 to 90.3%. To reveal the versatility and applicability of this protocol, the late-stage modification of an antiepileptic drug to obtain oxcarbazepine was further conducted.
- Ma, Cunfei,Meng, Qingwei,Tang, Xiaofei,Yu, Zongyi,Yun, Lei,Zhao, Jingnan
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p. 1612 - 1618
(2021/07/21)
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- Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
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Irradiated by visible light, the recyclable (PhTe)2-catalyzed oxidative deoximation reaction could occur under mild conditions. In comparison with the thermo reaction, the method employed reduced catalyst loading (1 mol% vs. 2.5 mol%), but afforded elevated product yields with expanded substrate scope. This work demonstrated that for the organotellurium-catalyzed reactions, visible light might be an even more precise driving energy than heating because it could break the Te–Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents (e.g., heterocycles) of substrates. The use of O2 instead of explosive H2O2 as oxidant affords safer reaction conditions from the large-scale application viewpoint.
- Deng, Xin,Qian, Rongrong,Zhou, Hongwei,Yu, Lei
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supporting information
p. 1029 - 1032
(2020/10/23)
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- PhSe(O)OH/NHPI-catalyzed oxidative deoximation reaction using air as oxidant
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A novel oxidative deoximation method was developed in this article. Compared with the reported organoselenium-catalyzed oxidative deoximation reaction, this reaction employed N-hydroxyphthalimide (NHPI) as the co-catalyst, so that the oxidative deoximation reaction could utilize air as oxidant in the green DMC solvent under mild reaction conditions. Control experiments and X-ray photoelectron spectroscopy (XPS) analysis results indicated that NHPI was essential for activating the catalytic organoselenium species. It could accelerate the activation of molecular oxygen in air to promote the reaction process. The reaction can avoid metal residues in product and is of potential application values in pharmaceutical industry due to the transition metal-free process.
- Shi, Yaocheng,Wang, Feng,Yang, Chenggen,Yu, Lei
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- Ruthenium-on-Carbon-Catalyzed Facile Solvent-Free Oxidation of Alcohols: Efficient Progress under Solid-Solid (Liquid)-Gas Conditions
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A protocol for the ruthenium-on-carbon (Ru/C)-catalyzed solvent-free oxidation of alcohols, which proceeds efficiently under solid-solid (liquid)-gas conditions, was developed. Various primary and secondary alcohols were transformed to corresponding aldehydes and ketones in moderate to excellent isolated yields by simply stirring in the presence of 10% Ru/C under air or oxygen conditions. The solvent-free oxidation reactions proceeded efficiently regardless of the solid or liquid state of the substrates and reagents and could be applied to gram-scale synthesis without loss of the reaction efficiency. Furthermore, the catalytic activity of Ru/C was maintained after five reuse cycles.
- Park, Kwihwan,Jiang, Jing,Yamada, Tsuyoshi,Sajiki, Hironao
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p. 1200 - 1205
(2021/12/29)
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- A novel two-dimensional metal-organic framework as a recyclable heterogeneous catalyst for the dehydrogenative oxidation of alcohol and theN-arylation of azole compounds
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A novel metal-organic framework (MOF) with two-dimensional (2D) crystal structure was developed using Cu(NO3)2·3H2O and 2,2′,5,5′-tetramethoxy-[1,1′-biphenyl]-4,4′-dicarboxylic acid. Further, its structure was characterized using infrared spectroscopy, thermogravimetry, X-ray diffraction, and X-ray crystallography. The activated Cu-MOF was used to catalyze the dehydrogenative oxidation of alcohol andN-arylation of azole compounds. Furthermore, it could be easily recovered and reused.
- Liu, Chengxin,Cui, Jin,Wang, Yufang,Zhang, Mingjie
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p. 11739 - 11744
(2021/03/31)
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- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- METHOD FOR PRODUCING OXIDE USING BETA-MANGANESE DIOXIDE
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With the object of efficiently producing an oxidation product, the present invention provides a method for producing an oxidation product by oxidizing a raw material compound in the presence of oxygen, wherein the raw material compound is oxidized in the presence of manganese dioxide having a crystal structure of β-type.
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Paragraph 0099
(2021/10/15)
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- Method for preparing aldehyde ketone compound through olefin oxidation
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The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
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Paragraph 0012-0019
(2021/04/07)
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- Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
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A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
- Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
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p. 13848 - 13852
(2021/04/22)
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- Fe-S Catalyst Generated in Situ from Fe(III)- And S3?--Promoted Aerobic Oxidation of Terminal Alkenes
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An iron-sulfur complex formed by the simple mixture of FeCl3 with S3?- generated in situ from K2S is developed and applied to selective aerobic oxidation of terminal alkenes. The reaction was carried out under an atmosphere of O2 (balloon) and could proceed on a gram scale, expanding the application of S3?- in organic synthesis. This study also encourages us to explore the application of an Fe-S catalyst in organic reactions.
- Ai, Jing-Jing,Huang, Cheng-Mi,Li, Jian,Liu, Bei-Bei,Rao, Weidong,Wang, Fei,Wang, Shun-Yi
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supporting information
p. 4705 - 4709
(2021/06/28)
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- Photo-induced oxidative cleavage of C-C double bonds of olefins in water
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The carbonyl compounds, synthesized by the oxidative cleavage of their corresponding olefins, are of great significance in organic synthesis, especially aryl ketones. We have developed a gentle and effective protocol, using acid red 94 as the organic metal-free photocatalyst, O2 as the oxidant, and water as the solvent. Under visible light irradiation, aryl ketone derivatives were obtained in moderate to excellent yields, showing good economic and environmental advantages.
- Zhang, Yilan,Yue, Xiaoguang,Liang, Chenfeng,Zhao, Jianming,Yu, Wenbo,Zhang, Pengfei
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supporting information
(2021/08/27)
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- Electrochemical Difunctionalization of Styrenes via Chemoselective Oxo-Azidation or Oxo-Hydroxyphthalimidation
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Atom- and step-economic oxo-azidation and oxo-hydroxyphthalimidation of styrenes have been developed under mild electrolytic conditions, respectively. Various valuable alpha-azido or hydroxyphthalimide aromatic ketones were synthesized efficiently from readily available styrenes, azides, and N-hydroxyphthalimides. Mechanism studies show that two different pathways involved in these two transformations.
- Jiang, Haobin,Wang, Feng,Ye, Zenghui,Zhang, Fengzhi,Zhu, Rongjin
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supporting information
p. 8240 - 8245
(2021/11/17)
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- Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanoneviaCeCl3catalysis
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A Ce-catalyzed strategy is developed to produce biaryl methanonesviaphotooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
- Xie, Pan,Xue, Cheng,Du, Dongdong,Shi, SanShan
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supporting information
p. 6781 - 6785
(2021/08/20)
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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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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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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 0029
(2021/09/26)
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- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
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With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
- Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
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supporting information
p. 5936 - 5943
(2021/08/23)
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- Aerobic oxidative C?C bond cleavage of aromatic alkenes by a high valency iron-containing perovskite catalyst
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High valency iron-containing perovskite catalyst BaFeO3-dcould efficiently promote the additive-free oxidative C?C bond cleavage of various aromatic alkenes to the corresponding aldehydes or ketones using O2as the sole oxidant. This system was applicable to the gram-scale oxidation of 1,1-diphenylethylene, in which 2.71 g (75% yield) of the analytically pure ketone could be isolated.
- Shibata, Satomi,Kamata, Keigo,Hara, Michikazu
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p. 2369 - 2373
(2021/04/22)
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- Method for preparing carbonyl compound through oxidative cleavage of visible light excitation aqueous solution quantum dot catalytic olefin compound
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The invention provides a method for preparing carbonyl compounds through oxidative cleavage of a visible light excitation aqueous solution quantum dot catalytic olefin compound. Belong to photocatalysis synthesis technical field. To the method, an aqueous solution quantum dot is used as a photocatalyst, and an aqueous solution quantum dot activated molecular oxygen catalytic oxidation aromatic alkene compound is excited by visible light to be cracked to prepare a carbonyl compound. Low-loading capacity is used, a simple aqueous solution quantum dot is used as a catalyst, the yield of the carbonyl compound is high, TON more than ten millions are obtained. The reaction conditions are mild, water serves as a main solvent for the reaction, and the carbonyl compound can be obtained by catalytic olefin compound oxidation cracking without addition of a cocatalyst or the like. The method is simple to operate, wide in substrate range and low in cost.
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Paragraph 0040
(2021/11/10)
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- Catalytic epoxidation of β-ionone with molecular oxygen using selenium-doped silica materials
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A novel Se-doped silica material was fabricated, and this easily prepared material could be used as an efficient recyclable catalyst for β-ionone oxidation. Interestingly, by doping with fluorine in the catalyst, the reaction selectivity was significantly enhanced to produce the important pharmaceutical intermediate β-ionone epoxide selectively. Characterization of the materials indicated that by doping with F, the electropositivity of the catalytic Se species was obviously enhanced due to the strong electron-withdrawing features of F, and this was a key factor for controlling the reaction selectivity in the β-ionone epoxidation reaction. The electropositivity of a silica support might also increase and the reinforced electropositivity of Si sites might be beneficial for the adsorption of a β-ionone substrate and for the contact of the electron-enriched endocyclic C-C with the catalyst.
- Cao, Kuanhong,Jing, Xiaobi,Li, Peizi,Liu, Yonghong,Yu, Lei
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p. 17241 - 17246
(2021/10/04)
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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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- Visible-light-induced oxidative coupling of vinylarenes with diselenides leading to α-aryl and α-alkyl selenomethyl ketones
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A visible-light-induced oxidative coupling of diselenides with readily available vinylarenes is demonstrated. This benign protocol allows one to access a wide range of α-aryl and α-alkyl selenomethyl ketones in good yields with excellent functional group compatibility. The distinct advantages of this protocol over all previous methods include the use of a green solvent and air as an oxidant and the lack of a photocatalyst, a base, and an oxidant as well as better green chemistry matrices. Furthermore, the title reaction can be performed with natural sunlight, the most sustainable energy source imaginable. Additionally, the mild reaction conditions, easy operation and suitability for the modification of styrene-functionalized biomolecules make the current reaction system a more attractive method for the synthesis of a variety of medicinal and agrochemical compounds of interest.
- Liu, Gong-Qing,Yi, Wei,Wang, Peng-Fei,Liu, Ji,Ma, Meng,Hao, Da-Yun,Ming, Liang,Ling, Yong
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supporting information
p. 1840 - 1846
(2021/03/09)
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- Photocatalyst-free visible-light-promoted quinazolinone synthesis at room temperature utilizing aldehydes generatedin situ viaC=C bond cleavage
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This is the first report on a facile tandem route for synthesizing quinazolinones at room temperature from various aminobenzamides andin situ-generated aldehydes. The latter was formedviaC=C bond cleavage, and the overall reaction proceeded using molecular oxygen as a clean oxidant in the absence of a photocatalyst. Visible light, which was indispensable for the entire course of the reaction, played multiple roles. It initially cleaved styrene to an aldehyde, then facilitated its cyclization with ano-substituted aniline, and finally promoted the dehydrogenation of the cyclized intermediate. The previous step provided the feedstock for the next step in the reaction, thereby preventing volatilization, oxidation, and polymerization of the aldehyde. Thus, the overall process is simple, environmentally benign, and economically feasible.
- Xie, Zongbo,Lan, Jin,Yan, Liyuan,Chen, Xuehua,Li, Qian,Meng, Jia,Le, Zhanggao
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p. 2436 - 2441
(2021/04/02)
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- Thiol-initiated photocatalytic oxidative cleavage of the C=C bond in olefins and its extension to direct production of acetals from olefins
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The oxidative cleavage of olefins to produce aldehydes/ketones is an important reaction in organic syntheses. In this manuscript, a mild and operationally simple protocol for the aerobic oxidation of olefins to produce carbonyl compounds was realized over ZnIn2S4under visible light, using air as the oxidant and a thiol as the initiator. It was proposed that the photogenerated holes over ZnIn2S4attack the thiol to produce thiyl radicals, which initiate the oxidative cleavage of the C=C bond in olefins to produce aldehydes/ketones. By further coupling with the condensation between the as-obtained aldehydes/ketones and alcohols, this strategy can also be applied to the production of different acetals directly from the olefins. This study demonstrates a new pathway to realize the oxidative cleavage of olefins to produce aldehydes/ketones, and also provides a new protocol for the production of acetals directly from the olefins.
- Wang, Xinglin,Li, Yuanyuan,Li, Zhaohui
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p. 1000 - 1006
(2021/02/26)
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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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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- Cobalt-Catalyzed Aerobic Oxidative Cleavage of Alkyl Aldehydes: Synthesis of Ketones, Esters, Amides, and α-Ketoamides
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A widely applicable approach was developed to synthesize ketones, esters, amides via the oxidative C?C bond cleavage of readily available alkyl aldehydes. Green and abundant molecular oxygen (O2) was used as the oxidant, and base metals (cobalt and copper) were used as the catalysts. This strategy can be extended to the one-pot synthesis of ketones from primary alcohols and α-ketoamides from aldehydes.
- Li, Tingting,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 9737 - 9741
(2021/05/31)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- PhIO-Mediated oxidative dethioacetalization/dethioketalization under water-free conditions
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Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.
- Du, Yunfei,Ouyang, Yaxin,Wang, Xi,Wang, Xiaofan,Yu, Zhenyang,Zhao, Bingyue,Zhao, Kang
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- Method for preparing aldehyde compound through olefin oxidation
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The invention provides a simple synthesis method for preparing an aldehyde compound through olefin oxidation, and the related preparation method is an olefin oxidative cracking reaction in which oxygen participates, and comprises the following specific steps: in the presence of a solvent and an oxidant, performing oxidative cracking on an olefin raw material to prepare a corresponding aldehyde product. Compared with a traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environmental protection, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has wide application prospects in synthesis of aldehyde medical intermediates and chemical raw materials.
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Paragraph 0031-0035
(2021/06/09)
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- Intercepting a transient non-hemic pyridine: N -oxide Fe(iii) species involved in OAT reactions
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In the context of bioinspired OAT catalysis, we developed a tetradentate dipyrrinpyridine ligand, a hybrid of hemic and non-hemic models. The catalytic activity of the iron(iii) derivative was investigated in the presence of iodosylbenzene. Unexpectedly, MS, EPR, M?ssbauer, UV-visible and FTIR spectroscopic signatures supported by DFT calculations provide convincing evidence for the involvement of a relevant FeIII-O-NPy active intermediate. This journal is
- Vo, Nhat Tam,Herrero, Christian,Guillot, Régis,Inceoglu, Tanya,Leibl, Winfried,Clémancey, Martin,Dubourdeaux, Patrick,Blondin, Geneviève,Aukauloo, Ally,Sircoglou, Marie
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supporting information
p. 12836 - 12839
(2021/12/10)
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- Dehalogenation reaction photocatalyzed by homoleptic copper(i) complexes associated with strongly reductive sacrificial donors
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In order to perform challenging reduction reactions with light, at low cost and low toxicity, we aim at using for the first time a reductive quenching cycle with a simple, strongly colored homoleptic copper(i) complex [Cu(dipp)2]+(dipp = 2,9-diisopropyl-1,10-phenanthroline). Complexes of this family being weak photo-oxidants, we specifically designed and synthesized powerful, recyclable sacrificial electron donors D. We demonstrate that, during irradiation with LED light in the presence of D, the strong reductant [Cu(dipp)2]0is efficiently photo-generated. Further, we present the first photochemical reaction using photo-generated [Cu(dipp)2]0and evidence that the kinetics of the overall reaction are strongly affected by the oxidation potential of the sacrificial donorE(D+/D). Adapting the thermodynamics of sacrificial donors D and [Cu(dipp)2]+has thus allowed us to unlock a brand new concept, giving access to cheap, non-toxic solar light-generated very strong reductive power.
- Blart, Errol,Gimeno, Lea,Mall Haidaraly, Kevin,Pellegrin, Yann,Queffélec, Clémence
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p. 6041 - 6047
(2021/09/28)
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- Discovery and characterization of a novel perylenephotoreductant for the activation of aryl halides
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To develop a photocatalyst with catalytical activity for substrates with low reactivities is always highly desired. Herein, based on the principle of structure–property relationships, we rationally designed the natural product cercosporin, the naturally occurring perylenequinonoid pigment, to develop a novel organic perylenephotoreductant, hexacetyl reduced cercosporin (HARCP), through structural manipulation. Compared with cercosporin, HARCP shows prominent electrochemical and photophysical characteristics with greatly improved photoreductive activity, fluorescence lifetime and fluorescence quantum yield. These properties allowed HARCP as a powerful photoreductant to efficiently realize a series of benchmark reactions, including photoreduction, alkoxylation and hydroxylation to construct C–H and C–O bonds using aryl halides as substrates under mild conditions, all of which have never been achieved by the same photocatalyst. Thus, this study well supports the notion that the principle between structural manipulation and photocatalytic activity is of great significance to design customized photocatalysts for photoredox chemistry.
- Guo, Baodang,Huang, Shuping,Li, Jia,Li, Min,Liu, Xuanzhong,Rao, Yijian,Wu, Yawen,Yin, Huimin,Yuan, Zhenbo,Zhang, Yan
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p. 111 - 120
(2021/06/16)
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