- Impact of metalloporphyrin-based porous coordination polymers on catalytic activities for the oxidation of alkylbenzene
-
Seven metalloporphyrin-based porous coordination polymers: Feш (TZP)Poly (CP1), CoII (TZP)Poly (CP2), NiII (TZP)Poly (CP3), CuII (TZP)Poly (CP4), ZnII (TZP)Poly (CP5), MnII (TZP)Poly (CP6),
- Du, Yan xia,Lü, Xiang-fei,Li, Jun,Mele, Giuseppe,Ni, Wan-kui,Zhao, Yong-guo
-
-
Read Online
- Preparation, characterization, and catalytic application of nano Ag/ZnO in the oxidation of benzylic C-H bonds in sustainable media
-
Nano Ag/ZnO is successfully synthesized by a new simple and low cost method employing Zn(NO3)2·6H2O, AgNO3, and urea. X-ray diffraction (XRD), transmission electron microscopy (TEM), adsorption/desorption porosi
- Hosseini-Sarvari, Mona,Ataee-Kachouei, Tahereh,Moeini, Fatemeh
-
-
Read Online
- Photochemistry of α-fluorocycloalkanones and α-bromo- α- fluorocycloalkanones
-
Uv irradiation of a cyclohexane solution of 2-fluoro-1-indanone, 2-fluoro-1-tetralone, or 2-fluoro-1-benzosuberone resulted in the formation of a radical product (1-indanone, 1-tetralone, or 1-benzosuberone), and the degree of conversion depended on the ring size of the cycloalkanone. On the other hand, both radical as well as ionic products were formed when 2-bromo-2-fluoro derivatives of 1-indanone, 1-tetralone, or 1-benzosuberone were irradiated.
- Sket,Zupancic,Zupan
-
-
Read Online
- Intramolecular cyclization using palladium-catalyzed arylation toward formyl and nitro groups
-
Intramolecular arylation of properly designed substrates bearing a formyl or nitro terminating group was achieved employing a PdCl2(Ph3P)2- Cs2-CO3 catalyst system to form various carbocyclic compounds. Arylation toward the formyl group occurred at the α-position (α-arylation) or at the carbonyl carbon (carbonyl-arylation) depending on the structure of the substrates and on the reaction solvent. The α-arylated secondary nitro group was partially transformed to ketone, whereas the tertiary nitro group was partially eliminated to a styrene type of olefin.
- Muratake, Hideaki,Nakai, Hiroshi
-
-
Read Online
- Ag-Catalyzed ring-opening of tertiary cycloalkanols for C-H functionalization of cyclic aldimines
-
We firstly describe a silver-catalyzed direct C-H functionalization of cyclic aldimines with cyclopropanols and cyclobutanolsviaa radical-mediated C-C bond cleavage strategy. The desired products were generated in decent yields with wide substrate scope under mild reaction conditions. In addition, a gram-scale reaction and synthetic transformation of the product were performed.
- Wang, Jingjing,Liu, Xue,Wu, Ziyan,Li, Feng,Zhang, Ming-Liang,Mi, Yiman,Wei, Junhao,Zhou, Yao,Liu, Lantao
-
-
Read Online
- Heterogenization of [Cu(2,2′-bpy)Cl2] and [Cu(1,10-phen)Cl2] on polyoxometalates: New catalysts for the selective oxidation of tetralin
-
Mononuclear Cu(II) bipyridine (1) and phenantroline complexes (2) were synthesized and immobilized by different procedures on H3PW 12O40 polyoxometalate (POM). Characterization by XRD and SEM-EDX were performed to assess the preservation of the Keggin structure and stoichiometry of the complex. The immobilized complexes were tested as heterogeneous catalysts for the partial oxidation of tetralin (1,2,3,4-tetrahydronaphthalene) using hydrogen peroxide as oxidant in acetonitrile/water as solvent. [Cu(2,2′-bpy)Cl][H2PW 12O40] and [Cu(1,10-phen)Cl][H2PW 12O40] oxidized tetralin at room temperature, with 16 conversion with (2), to 1-tetralone and 2-tetralone with 83 selectivity. However, the selectivity for 1-tetralone was only 56. Different preparation methods for the heterogenization of these complexes on the POM Keggin unit were compared and used to enhance the selectivity to 1-tetralone to 75.
- Boltz,Blanc,Laugel,Pale,Louis
-
-
Read Online
- Wet alumina supported chromium(VI) oxide: Selective oxidation of alcohols in solventless system
-
A simple and selective method for the oxidation of alcohols to carbonyl compounds is described that occurs on wet alumina supported chromium(VI) oxide under solvent-free conditions and is expedited by microwave irradiation. Aliphatic primary alcohols provide the corresponding esters in moderate yield.
- Varma, Rajender S.,Saini, Rajesh K.
-
-
Read Online
- Chelating bis-N-heterocyclic carbene complexes of iron(II) containing bipyridyl ligands as catalyst precursors for oxidation of alcohols
-
Chelating bis-N-heterocyclic carbene (bis-NHC) complexes of iron(ii) containing pyridyl ligands have been prepared by the reaction of [FeCl2L] [L = bipy (1), phen (2)] with [LiN(SiMe3)2] and a bis(imidazolium) salt. The [F
- Pinto, Mara F.,Cardoso, Bernardo De P.,Barroso, Sónia,Martins, Ana M.,Royo, Beatriz
-
-
Read Online
- A traceless perfluorooctylsulfonyl tag for deoxygenation of phenols under microwave irradiation
-
The perfluorooctylsulfonyl group is introduced as a traceless tag for solution-phase palladium-catalyzed deoxygenation reactions. The synthetic efficiency is improved by microwave irradiation for reaction and fluorous solid-phase extraction for separation. Further application of this traceless tag for multistep synthesis of substituted hydantoin and pyrimidine is also described.
- Zhang, Wei,Nagashima, Tadamichi,Lu, Yimin,Chen, Christine Hiu-Tung
-
-
Read Online
- HCl-Catalyzed Aerobic Oxidation of Alkylarenes to Carbonyls
-
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
-
-
- Selective Aerobic Oxidation of Csp3-H Bonds Catalyzed by Yeast-Derived Nitrogen, Phosphorus, and Oxygen Codoped Carbon Materials
-
Nitrogen, phosphorus, and oxygen codoped carbon catalysts were successfully synthesized using dried yeast powder as a pyrolysis precursor. The yeast-derived heteroatom-doped carbon (yeast@C) catalysts exhibited outstanding performance in the oxidation of Csp3-H bonds to ketones and esters, giving excellent product yields (of up to 98% yield) without organic solvents at low O2pressure (0.1 MPa). The catalytic oxidation protocol exhibited a broad range of substrates (38 examples) with good functional group tolerance, excellent regioselectivity, and synthetic utility. The yeast-derived heteroatom-doped carbon catalysts showed good reusability and stability after recycling six times without any significant loss of activity. Experimental results and DFT calculations proved the important role of N-oxide (N+-O-) on the surface of yeast@C and a reasonable carbon radical mechanism.
- Ju, Zhao-Yang,Song, Li-Na,Chong, Ming-Ben,Cheng, Dang-Guo,Hou, Yang,Zhang, Xi-Ming,Zhang, Qing-Hua,Ren, Lan-Hui
-
supporting information
p. 3978 - 3988
(2022/03/16)
-
- Efficient and selective oxidation of hydrocarbons with tert-butyl hydroperoxide catalyzed by oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles
-
The catalytic activity of an oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles, γ-Fe2O3@[VO(salenac-OH)] in which salenac-OH = [9-(2′,4′-dihydroxyphenyl)-5,8-diaza-4
- Samani, Mahnaz,Ardakani, Mehdi Hatefi,Sabet, Mohammad
-
p. 1481 - 1494
(2022/01/22)
-
- Two transition-metal-modified Nb/W mixed-addendum polyoxometalates for visible-light-mediated aerobic benzylic C–H oxidations
-
The visible-light-induced selective oxidation of ubiquitous C–H bonds into valuable C=O bonds under aerobic conditions is one of the most attractive approaches for the construction of carbonyl-containing molecules. In this work, two transition metal-containing Nb/W mixed-addendum POMs dimers with the formula of K2Na2H5[(Fe(H2O)4)3(P2W15Nb3O62)2]?24H2O (POM[Fe]) and K2Na3H4[(Cr(H2O)4)3(P2W15Nb3O62)2]?32H2O (POM[Cr]) have been synthesized and characterized by various analytical and spectral techniques. POM[Fe] was proved to be an efficient photocatalyst for benzylic C–H oxidation under visible light and using oxygen as an oxidant to produce the corresponding carbonyl complex in good yields. A plausible mechanism involving superoxide radical was proposed for the catalytic reaction. POM[Fe] showed good reusability in the recycling experiments. IR spectroscopy and XRD analysis indicate that POM[Fe] can retain its integrity after catalysis.
- Chen, Xuenian,Gao, Fan,Li, Na,Li, Shujun,Ma, Yubin,Xiao, Wanru,Yu, Bing
-
supporting information
(2022/03/27)
-
- A Carbene Strategy for Progressive (Deutero)Hydrodefluorination of Fluoroalkyl Ketones
-
Hydrodefluorination is one of the most promising chemical strategies to degrade perfluorochemicals into partially fluorinated compounds. However, controlled progressive hydrodefluorination remains a significant challenge, owing to the decrease in the stre
- Bi, Xihe,Sivaguru, Paramasivam,Song, Qingmin,Wang, Zikun,Zanoni, Giuseppe,Zhang, Xiaolong,Zhang, Xinyu
-
supporting information
(2021/12/23)
-
- Selective Oxidation of Benzylic sp3C-H Bonds using Molecular Oxygen in a Continuous-Flow Microreactor
-
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
-
supporting information
p. 1612 - 1618
(2021/07/21)
-
- A Copper-Containing Polyoxometalate-Based Metal-Organic Framework as an Efficient Catalyst for Selective Catalytic Oxidation of Alkylbenzenes
-
A copper-containing polyoxometalate-based metal-organic framework (POMOF), CuI12Cl2(trz)8[HPW12O40] (HENU-7, HENU = Henan University; trz = 1,2,4-triazole), has been successfully synthesized and well-characterized. In addition, the excellent catalytic ability of HENU-7 has been proved by the selective oxidation of diphenylmethane. Under the optimal conditions, the diphenylmethane conversion obtained over HENU-7 is 96%, while the selectivity to benzophenone is 99%, which outperforms most noble-metal-free POM-based catalysts. Moreover, HENU-7 is stable to reuse for five runs without an obvious loss in activity and also can catalyze the oxidation of different benzylic C-H with satisfactory conversions and selectivities, which implied the significant catalytic activity and recyclability.
- Xu, Baijie,Xu, Qian,Wang, Quanzhong,Liu, Zhen,Zhao, Ruikun,Li, Dandan,Ma, Pengtao,Wang, Jingping,Niu, Jingyang
-
p. 4792 - 4799
(2021/04/09)
-
- SBA-15 Supported 1-Methyl-2-azaadamanane N-Oxyl (1-Me-AZADO) as Recyclable Catalyst for Oxidation of Alcohol
-
Herein, we designed and synthesized an SBA-15 supported 1-methyl-2-azaadamanane N-oxyl (1-Me-AZADO) and investigated its catalytic performance for selective oxidation of alcohols under Anelli's conditions. The first example of immobilization of 1-Me-AZADO was very important to advance the oxgenation effectively because this supported N-oxyl has excellent catalytic activity for oxidation of alcohols to carbonyl compounds, and more importantly, it can be conveniently recovered and reused at least 6 times without significant effect on its catalytic efficiency.
- Tian, Yangwu,Guo, Xiaqun,Li, Meichao,Li, Chunmei,Hu, Xinquan,Jin, Liqun,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu
-
supporting information
p. 3928 - 3932
(2021/05/26)
-
- Synthesis method of 3-bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one
-
The invention discloses a synthesis method of 3-bromine-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one, and belongs to the technical field of organic synthesis. The synthesis method comprises the steps that gamma-butyrolactone and benzene which are cheap and easy to obtain serve as starting raw materials, 2-bromo-1-tetralone, 2-bromo-3,4-dihydro-N-hydroxy-(2H)-naphthalimide and 3-bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one are synthesized in sequence . According to the synthetic method, gamma-butyrolactone and benzene are taken as starting raw materials, and 3-bromo-1,3,4,5-tetrahydro-2H-1-benzoazepin-2-one is obtained through cyclization reaction, bromination reaction, oxime forming reaction and Beckmann rearrangement reaction respectively. The method has the advantages of simple production process, low production cost, simplicity in operation, less three wastes, small environmental pollution and suitability for industrial production.
- -
-
Paragraph 0024
(2021/07/24)
-
- Chiral Yolk-Shell MOF as an Efficient Nanoreactor for Asymmetric Catalysis in Organic-Aqueous Two-Phase System
-
It remains a great challenge to introduce large and efficient homogeneous asymmetric catalysts into MOFs and other microporous materials as well as retain their degrees of freedom. Herein, a new heterogeneous strategy of homogeneous chiral catalysts is proposed, that is, to construct a yolk-shell MOFs-confined, large-size, and highly efficient homogeneous chiral catalyst, which can be used as a nanoreactor for asymmetric catalytic reactions.
- Shi, Shunli,Zhong, Yicheng,Hu, Zhuo,Wang, Lei,Yuan, Mingwei,Ding, Shunmin,Wang, Shuhua,Chen, Chao
-
supporting information
p. 12714 - 12718
(2021/09/11)
-
- Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
-
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
-
supporting information
p. 1029 - 1032
(2020/10/23)
-
- PhSe(O)OH/NHPI-catalyzed oxidative deoximation reaction using air as oxidant
-
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
-
-
- PhIO-Mediated oxidative dethioacetalization/dethioketalization under water-free conditions
-
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
-
-
- Electrochemical Difunctionalization of Styrenes via Chemoselective Oxo-Azidation or Oxo-Hydroxyphthalimidation
-
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
-
supporting information
p. 8240 - 8245
(2021/11/17)
-
- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
-
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
-
p. 5936 - 5943
(2021/08/23)
-
- Selective oxidation of alkenes to carbonyls under mild conditions
-
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
-
supporting information
p. 5549 - 5555
(2021/08/16)
-
- Aryl aldiketone and synthesis method thereof
-
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.
- -
-
Paragraph 0025
(2021/09/26)
-
- Cationic nickel(II) pyridinophane complexes: Synthesis, structures and catalytic activities for C-H oxidation
-
A series of nickel(II) pyridinophane complexes were synthesized and characterized by X-ray crystallographic analysis. Their IR spectra supported the existence of mononuclear nickel(II) complexes in solution. Furthermore, we conducted catalytic CH oxidation of cyclooctane with nickel(II) pyridinophanes as the catalysts. The activity of nickel(II) pyridinophanes was affected by steric hindrance around the nitrogen atoms.
- Nishimura, Tsubasa,Ando, Yuki,Shinokubo, Hiroshi,Miyake, Yoshihiro
-
supporting information
p. 1049 - 1052
(2021/05/19)
-
- An efficient and practical aerobic oxidation of benzylic methylenes by recyclable: N -hydroxyimide
-
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
-
p. 3003 - 3011
(2021/01/28)
-
- Efficient Aliphatic C-H Oxidation and C═C Epoxidation Catalyzed by Porous Organic Polymer-Supported Single-Site Manganese Catalysts
-
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
-
p. 10964 - 10973
(2021/09/08)
-
- Ferric ion concentration-controlled aerobic photo-oxidation of benzylic C–H bond with high selectivity and conversion
-
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
-
-
- V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
-
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.
-
p. 3594 - 3600
(2021/07/02)
-
- Gold complexes of bis-indazole-derived N-Heterocyclic carbene: Synthesis, structural characterizations, and catalysis
-
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
-
-
- Catalytic Highly Regioselective C-H Oxygenation Using Water as the Oxygen Source: Preparation of 17O/18O-Isotope-Labeled Compounds
-
We found that the oxygen atom of water is activated to iodosylbenzene derivatives via reversible hydrolysis of PhI(OOCR)2 and can be used to the oxygen source for ruthenium(bpga)-catalyzed site-selective C-H oxygenation. Ru(bpga)/PhI(OOCR)2/H2O system, sterically less bulky methinic and methylenic C-H bonds in various compounds can be converted to desired oxygen functional groups in a site-selective manner. Using this method, oxygen-isotope labeled compounds such as d-[3-17O/18O]-mannose can be prepared in a multigram scale.
- Doiuchi, Daiki,Uchida, Tatsuya
-
supporting information
p. 7301 - 7305
(2021/10/01)
-
- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
-
An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
-
supporting information
p. 7445 - 7449
(2021/10/02)
-
- Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
-
A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
- Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
-
p. 2134 - 2141
(2021/09/29)
-
- Visible-light photocatalytic selective oxidation of C(sp3)-H bonds by anion-cation dual-metal-site nanoscale localized carbon nitride
-
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
-
p. 4429 - 4438
(2021/07/12)
-
- Visible-Spectrum Solar-Light-Mediated Benzylic C-H Oxygenation Using 9,10-Dibromoanthracene As an Initiator
-
We report a visible-light-mediated benzylic C-H oxygenation reaction. The reaction is initiated by solar light or the blue LED activation of 9,10-dibromoanthracene in a reaction with oxygen and takes place at ambient temperature and air pressure. Secondary benzylic positions are oxygenated to ketones, while tertiary benzylic carbons are oxygenated to give hydroperoxides. Notably, cumene hydroperoxide is produced in a higher yield and at milder conditions than the currently employed industrial conditions.
- Santra, Sourav K.,Szpilman, Alex M.
-
p. 1164 - 1171
(2020/12/23)
-
- RUTHENIUM COMPLEX AND PRODUCTION METHOD THEREOF, CATALYST, AND PRODUCTION METHOD OF OXYGEN-CONTAINING COMPOUND
-
PROBLEM TO BE SOLVED: To provide a ruthenium complex that is particularly useful as a catalyst for oxidizing a substrate having a carbon-hydrogen bond. SOLUTION: The ruthenium complex represented by the general formula (i) or a cis conformer thereof is provided. In the general formula (i), R1 represents H, a phenyl group or a substituted phenyl group; R2 represents H, a phenyl group or an alkyl group; L1 represents halogen or water molecule; L2 represents triphenylphosphine, pyridine, imidazole or dimethylsulfoxide; X represents halogen; and n represents 1 or 2. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPO&INPIT
- -
-
Paragraph 0069-0071
(2021/01/29)
-
- LIGHT INDUCED CATALYTIC C-H OXYGENATION OF ALKANES
-
A method of oxygenating a benzylic C-H bond is provided. The method comprises light induced activation of an initiator and subsequent reaction with oxygen, resulting in the formation of free radicals. Subsequently, free radicals catalyze the reaction of the benzylic C-H bond with oxygen, thereby forming an oxygenated compound.
- -
-
Paragraph 00219-00220 00223-00224
(2021/04/02)
-
- Cu2O-CuO/Chitosan Composites as Heterogeneous Catalysts for Benzylic C?H Oxidation at Room Temperature
-
Recently, in catalysis, chitosan has been exploited as a macrochelating ligand for metal active species due to the presence of various functional groups in its structure. Moreover, copper-based catalysts are classified as one of the most environmentally friendly catalytic systems and their use for the oxidation of alkylarene has not been established much. Therefore, in this work, the hydrothermal synthesis of copper oxide-chitosan composites as heterogeneous catalysts for the benzylic C?H oxidation of alkylarene was investigated. Characterization results reveal mixed phases of CuO and Cu2O, inferring the ability of chitosan to act as a reducing sugar under the hydrothermal condition. The pre-existing interaction between copper species and chitosan as well as the co-existence of the Cu2O and CuO structures give rise to the efficient performance of the catalysts. The synthesized composites exhibit high activity for the oxidation of fluorene to 9-fluorenone at room temperature and small catalyst loading (1 mol % of Cu, >90 % conversion and 100 % selectivity). Superior TOF was observed, and a good scope of substrates can be converted to corresponding ketones in 48–97 % yields with these copper oxide-chitosan catalysts. In addition, the catalysts can be used for up to nine cycles without significant decrease of the activity.
- Kanarat, Jurin,Bunchuay, Thanthapatra,Klysubun, Wantana,Tantirungrotechai, Jonggol
-
p. 4833 - 4840
(2021/10/07)
-
- Engineering the large pocket of an (S)-selective transaminase for asymmetric synthesis of (S)-1-amino-1-phenylpropane
-
Amine transaminases offer an environmentally benign chiral amine asymmetric synthesis route. However, their catalytic efficiency towards bulky chiral amine asymmetric synthesis is limited by the natural geometric structure of the small pocket, representing a great challenge for industrial applications. Here, we rationally engineered the large binding pocket of an (S)-selective ?-transaminase BPTA fromParaburkholderia phymatumto relieve the inherent restriction caused by the small pocket and efficiently transform the prochiral aryl alkyl ketone 1-propiophenone with a small substituent larger than the methyl group. Based on combined molecular docking and dynamic simulation analyses, we identified a non-classical substrate conformation, located in the active site with steric hindrance and undesired interactions, to be responsible for the low catalytic efficiency. By relieving the steric barrier with W82A, we improved the specific activity by 14-times compared to WT. A p-p stacking interaction was then introduced by M78F and I284F to strengthen the binding affinity with a large binding pocket to balance the undesired interactions generated by F44. T440Q further enhanced the substrate affinity by providing a more hydrophobic and flexible environment close to the active site entry. Finally, we constructed a quadruple variant M78F/W82A/I284F/T440Q to generate the most productive substrate conformation. The 1-propiophenone catalytic efficiency of the mutant was enhanced by more than 470-times in terms ofkcat/KM, and the conversion increased from 1.3 to 94.4% compared with that of WT, without any stereoselectivity loss (ee > 99.9%). Meanwhile, the obtained mutant also showed significant activity improvements towards various aryl alkyl ketones with a small substituent larger than the methyl group ranging between 104- and 230-fold, demonstrating great potential for the efficient synthesis of enantiopure aryl alkyl amines with steric hindrance in the small binding pocket.
- Liu, He,Wang, Hualei,Wei, Dongzhi,Xie, Youyu,Xu, Feng,Xu, Xiangyang,Yang, Lin
-
p. 2461 - 2470
(2021/04/22)
-
- Regioselective Electrochemical Cyclobutanol Ring Expansion to 1-Tetralones
-
A mild electrochemical method for the regioselective preparation of 1-tetralones under environmentally friendly conditions from readily available cyclobutanols was developed. A series of aromatic- and heteroaromatic-fused 1-tetralones was accessed through ring expansion of the functionalized cyclobutanols via electrochemical generation of alkoxy radicals and intramolecular cyclization.
- Petti, Alessia,Natho, Philipp,Lam, Kevin,Parsons, Philip J.
-
supporting information
p. 854 - 858
(2021/01/12)
-
- Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom-Economy by Titanocene(III) Catalysis
-
Described here is a titanocene-catalyzed reaction for the synthesis of acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, with pendant epoxides. The reaction proceeds by catalysis in single-electron steps. The oxidative addition comprises an epoxide opening. An H-atom transfer, to generate a benzylic radical, serves as a radical translocation step, and an organometallic oxygen rebound as a reductive elimination. The reaction mechanism was studied by high-level dispersion corrected hybrid functional DFT with implicit solvation. The low-energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate. An interesting mechanistic aspect is that the oxidation of the benzylic center occurs under reducing conditions.
- Funk, Pierre,Richrath, Ruben B.,Bohle, Fabian,Grimme, Stefan,Gans?uer, Andreas
-
supporting information
p. 5482 - 5488
(2021/02/03)
-
- Mangana(iii/iv)electro-catalyzed C(sp3)-H azidation
-
Manganaelectro-catalyzed azidation of otherwise inert C(sp3)-H bonds was accomplished using most user-friendly sodium azide as the nitrogen-source. The operationally simple, resource-economic C-H azidation strategy was characterized by mild reaction conditions, no directing group, traceless electrons as the sole redox-reagent, Earth-abundant manganese as the catalyst, high functional-group compatibility and high chemoselectivity, setting the stage for late-stage azidation of bioactive compounds. Detailed mechanistic studies by experiment, spectrophotometry and cyclic voltammetry provided strong support for metal-catalyzed aliphatic radical formation, along with subsequent azidyl radical transfer within a manganese(iii/iv) manifold.
- Meyer, Tjark H.,Samanta, Ramesh C.,Del Vecchio, Antonio,Ackermann, Lutz
-
p. 2890 - 2897
(2021/03/14)
-
- Single-atom cobalt-fused biomolecule-derived nitrogen-doped carbon nanosheets for selective oxidation reactions
-
Non-noble metal single-atom catalysts hold great promise in selective oxidation reactions, although the progress is still unsatisfactory because of the synthesis challenge and the lack of mechanistic interpretations. Herein, we develop a biomolecule-based strategy to synthesize isolated Co single atom site catalysts by one-step pyrolysis of guanosine and Co precursors. Due to the abundant hydrogen bonding and π-π interaction of guanosine, the as-synthesized Co-N-C catalysts present a hierarchical porous two-dimensional (2D) nanostructure with an ultrahigh specific surface area, large pore volume, and high density of cobalt single atoms. Aberration-corrected electron microscopy and X-ray photoelectron spectroscopy reveal that Co species are present as isolated single sites and stabilized by nitrogen-doped carbon nanosheets. These characteristics make Co-GS-900 suitable as an efficient catalyst for selective oxidation of aromatic alkanes. For oxidation of ethylbenzene, Co-GS-900 exhibits a superior performancefwith 91% conversion and 98% selectivity of acetophenone.
- Huang, Haitao,Wei, Qiao-Hua,Xia, Miao,Xie, Zailai,Zhang, Xuefei
-
p. 14276 - 14283
(2021/07/13)
-
- POLITAG-Pd(0) catalyzed continuous flow hydrogenation of lignin-derived phenolic compounds using sodium formate as a safe H-source
-
Phenols are aromatic biobased compounds and as they are accessible from lignin depolymerization, they can be a useful platform chemicals to produce value-added products. Herein we report our recent investigations on the definition of an approach to the efficient continuous flow selective hydrogenation of phenols in water. Our protocol is based on the use of sodium formate as a clean and safe hydrogen source in combination with our newly defined heterogeneous POLITAG-Pd(0) catalytic system. POLITAG is a polymeric heterogeneous support decorated with pincer-type ionic ligands proven to be highly efficient for the stabilization of Pd(0) nanoparticles. The results obtained are remarkable in comparison with other protocols that employ sodium formate as H-source. Indeed, our investigation has been extended to a variety of differently substituted phenolic compounds that have been hydrogenated with excellent to good selectivity in continuous flow conditions. Durability of the catalyst has been also tested with a representative continuous processing of over 100 mmol that showed no loss in efficiency and minimal metal leaching.
- Campana, Filippo,Ferlin, Francesco,Silvetti, Matteo,Trombettoni, Valeria,Vaccaro, Luigi,Valentini, Federica
-
-
- Enantioselective Hydroxylation of Benzylic C(sp3)-H Bonds by an Artificial Iron Hydroxylase Based on the Biotin-Streptavidin Technology
-
The selective hydroxylation of C-H bonds is of great interest to the synthetic community. Both homogeneous catalysts and enzymes offer complementary means to tackle this challenge. Herein, we show that biotinylated Fe(TAML)-complexes (TAML = Tetra Amido Macrocyclic Ligand) can be used as cofactors for incorporation into streptavidin to assemble artificial hydroxylases. Chemo-genetic optimization of both cofactor and streptavidin allowed optimizing the performance of the hydroxylase. Using H2O2 as oxidant, up to ～300 turnovers for the oxidation of benzylic C-H bonds were obtained. Upgrading the ee was achieved by kinetic resolution of the resulting benzylic alcohol to afford up to >98% ee for (R)-tetralol. X-ray analysis of artificial hydroxylases highlights critical details of the second coordination sphere around the Fe(TAML) cofactor.
- Barnet, Maxime,Peterson, Ryan L.,Rebelein, Johannes G.,Rumo, Corentin,Serrano-Plana, Joan,Ward, Thomas R.
-
supporting information
p. 10617 - 10623
(2020/07/04)
-
- Oxyfunctionalization of Alkanes Based on a Tricobalt(II)-Substituted Dawson-Type Rhenium Carbonyl Derivative as Catalyst
-
POM-supported metal carbonyl derivatives (PMCDs) represent a family of tremendous potential catalysts owing to their peculiar physical and chemical properties. Yet low-valence transition metal-substituted Dawson-type PMCD catalysts are uncommon. Hence, we synthesized a tricobalt-substituted PMCDs by conventional aqueous solution method, [Na(H2O)5](NH4)7[P2W15O56Co3(H2O)3(OH)3Re(CO)3]·13H2O (1), and characterized by single crystal X-ray diffraction crystallography, IR, and thermogravimetric analyses (TGA), etc. The obtained compound 1 was employed as a catalyst for the oxidation of diphenylmethane (DPM) to benzophenone, giving 96.8percent yield in the presence of tert-butyl hydroperoxide (TBHP) and pyridine. The control experiments indicate that Co metal ion plays an important role in the catalytic reactions. As a side note, the electrospray ionization mass spectrometry (ESI-MS) and UV spectroscopy showed that 1 can retain its integrity in solution, and magnetic measurements indicated that 1 exhibited a weaker ferromagnetic interaction at low temperature.
- Ma, Xinyi,Wang, Ping,Liu, Zhihao,Xin, Changhui,Wang, Siyu,Jia, Jiage,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
-
p. 8690 - 8698
(2020/07/03)
-
- Green synthesis method of medical intermediate benzocyclohexanone compound
-
The invention provides a green synthesis method of a benzocyclohexanone compound, and belongs to the technical field of organic synthesis. The method provided by the invention comprises the followingsteps: by taking 4-phenylbutyric acid as a raw material, firstly carrying out reflux reaction with oxalyl chloride in dichloromethane, carrying out vacuum evaporation to dryness to obtain a crude product of the 4-phenylbutyryl chloride compound, then dissolving the crude product in a solvent, adding a metal-doped modified molecular sieve catalyst to start reaction, and stirring the solution at different temperatures to carry out ring closing reaction, thereby obtaining the product; and after the reaction is finished, carrying out suction filtration, solvent washing, column chromatography purification and other operations to obtain the target product benzocyclohexanone compound. The synthesis method disclosed by the invention is environment-friendly in reaction and simple and convenient tooperate, the catalyst can be recycled, and the synthesis method is suitable for green synthesis of the benzocyclohexanone compound.
- -
-
Paragraph 0026-0028; 0047-0052
(2020/12/30)
-
- Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
-
Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is
- Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
-
p. 6600 - 6613
(2020/11/16)
-
- 9,10-Dihydroanthracene auto-photooxidation efficiently triggered photo-catalytic oxidation of organic compounds by molecular oxygen under visible light
-
The development of mild and efficient process for the selective oxidation of organic compounds by molecular oxygen (O2) can be one of the key technologies for synthesizing oxygenates. This paper discloses an efficient and mild synthesis protocol for the O2-involved ethylbenzene (EB) photooxidation triggered by 910-dihydroanthracene (DHA) auto- photooxidation in acetone under visible light illumination, which can achieve 87.7 percent EB conversion and 99.5 percent acetylacetone (ACP) selectivity under ambient conditions. Also, 62.9 percent EB conversion and 96.3 percent ACP selectivity is obtained in air atmosphere. Furthermore, this protocol has a good adaptability for the photooxidation of other organic substrates such as tetrahydronaphthalene, diphenylmethane, toluene, cyclohexane, cyclohexene, alcohol, methylfuran and thioether to their corresponding oxygenates. A series of control and quenching tests, combined with EPR spectra, suggest that the photo-excited DHA can transfer its photo-electron to O2 to yield a superoxide radical anion (O2??), then DHA is preferentially oxidized to anthraquinone (AQ) by the active O2?? owing to its high reactivity. Finally, the in situ generated AQ as an active photo-catalyst can achieve the photooxidation of EB and other organic compounds by O2. The present photo-autoxidation protocol gives a good example for the O2-based selective oxidation of inert hydrocarbons under mild conditions.
- Chen, Mengke,Deng, Youer,Fu, Zaihui,Hu, Wenwei,Jiang, Dabo,Liu, Yachun,Mao, Feng,Su, Anqun,Yang, Bo,Zhang, Chao
-
-
- Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN
-
A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3-dioxanes, 1,3-dioxolanes and 1,3-oxathianes quantitatively. As a possible extension of this method, it was also shown that nitrogenated substrates such as hydrazones, N-tosylhydrazones, and ketimines reacted well under these conditions to give the expected ketones in high yields. The methodology proposed herein is a good alternative to the existing methods since it does not use metals, oxidants, reducing agents, acidic or basic media, and keto-products were obtained in high to excellent yields.
- Yao, Yunxin,Zhao, Guangkuan,Hamze, Abdallah,Alami, Mouad,Provot, Olivier
-
p. 5775 - 5779
(2020/08/17)
-
- Pyrazoles: 'one-pot' synthesis from arenes and carboxylic acids
-
A rapid and efficient method for 'one-pot' synthesis of pyrazoles from (hetero)arenes and carboxylic acids via successive formation of ketones and β-diketones followed by heterocyclization with hydrazine has been developed. The utility of the RCOOH/TfOH/TFAA acylation system for intermediate production of ketones and 1,3-diketones is a key feature of this approach. The preliminary evaluation of the anticancer activity of the synthesized pyrazoles is performed.
- Gong, Ming,Kim, Jung Keun,Kovalev, Vladimir V.,Kovaleva, Olga V.,Shokova, Elvira A.,Tafeenko, Viktor A.,Wu, Yangjie
-
p. 5625 - 5638
(2020/08/21)
-
- Identification of Novel Unspecific Peroxygenase Chimeras and Unusual YfeX Axial Heme Ligand by a Versatile High-Throughput GC-MS Approach
-
Catalyst discovery and development requires the screening of large reaction sets necessitating analytic methods with the potential for high-throughput screening. These techniques often suffer from substrate dependency or the requirement of expert knowledge. Chromatographic techniques (GC/LC) can overcome these limitations but are generally hampered by long analysis time or the need for special equipment. The herein developed multiple injections in a single experimental run (MISER) GC-MS technique allows a substrate independent 96-well microtiter plate analysis within 60 min. This method can be applied to any laboratory equipped with a standard GC-MS. With this concept novel, unspecific peroxygenase (UPO) chimeras, could be identified, consisting of subdomains from three different fungal UPO genes. The GC-technique was additionally applied to evaluate an YfeX library in an E. coli whole-cell system for the carbene-transfer reaction on indole, which revealed the thus far unknown axial heme ligand tryptophan.
- Knorrscheidt, Anja,Püllmann, Pascal,Schell, Eugen,Homann, Dominik,Freier, Erik,Weissenborn, Martin J.
-
p. 4788 - 4795
(2020/07/21)
-
- Iron(III) 5,15-diazaporphyrin catalysts for the direct oxidation of C(sp3)-H bonds
-
5,15-Diazaporphyrins are porphyrin analogues with imine-type sp2-hybridized nitrogen atoms at the meso-positions. Even though these compounds are more electron-deficient than regular porphyrins, the use of iron diazaporphyrins as catalysts has not been reported. Herein, we disclose the synthesis, structure, and electronic properties of iron(III) 5,15-diazaporphyrins. We evaluate their structures and electronic natures by X-ray analysis and electrochemical analyses. We also demonstrate that chloroiron(III) 5,15-diazaporphyrins exhibit high catalytic activity in the direct oxidation of alkanes due to their intrinsic electron-deficient nature. On the basis of stoichiometric reactions of iron(III) diazaporphyrin with iodosylbenzene as an oxidant, it was possible to demonstrate the existence of an iodosylbenzene-iron diazaporphyrin adduct reaction intermediate that serves as a reservoir to generate oxo-iron species.
- Ikeue, Takahisa,Miyake, Yoshihiro,Nishimura, Tsubasa,Shinokubo, Hiroshi,Shoji, Osami
-
supporting information
p. 15751 - 15756
(2020/11/20)
-
- Highly selective electrocatalytic oxidation of benzyl C-H using water as safe and sustainable oxygen source
-
The selective oxidation of C-H bond is critical for feedstock manufacturing in chemical industry. Current strategies typically involve the use of oxygen or peroxide as the oxidation reagent under high temperature, which sets severe challenges in production sustainability and industrial safety. Herein, we demonstrate an environmental-friendly and safe electrocatalytic strategy for the selective oxidation of benzyl group to ketones at ambient conditions, while using water as the sole oxygen source. Water addition reduces the onset potential of anodic C-H oxidation, and produces 1-tetralone with satisfying conversion and excellent ketone to alcohol ratio. Layered MnO2 catalysts (with rich oxygen vacancies) further adjust the water affinity and facilitate the oxidation, leading to a significantly improved faradaic efficiency. This journal is
- Ding, Mengning,Li, Xiaoshan,Sun, Yuxia,Xie, Jin,Xu, Wentao,Yang, Miao
-
supporting information
p. 7543 - 7551
(2020/11/18)
-
- Method for directly oxidizing benzylic C-H bond to ketone or acid
-
The invention discloses a method for directly oxidizing benzylic C-H bonds into ketone or acid. A target product is obtained through an oxidation reaction with a compound containing benzylic C-H bondsas a substrate, trichloroisocyanuric acid as an oxidizing agent and sodium bromide and tetramethyl piperidine nitrogen oxide as catalysts. The oxidizing agent and the catalysts are cheap and easy toobtain, transport and store; the oxidative catalysis effect is good; the reaction condition is mild, the requirement and effect of harsh reaction conditions on equipment are avoided, and the method issuitable for industrial mass production. The use of a large quantity of heavy metal salts is avoided, and environmental pollution is further avoided.
- -
-
Paragraph 0038-0041
(2020/12/14)
-
- Visible-Light-Triggered Quantitative Oxidation of 9,10-Dihydroanthracene to Anthraquinone by O2 under Mild Conditions
-
The development of mild and efficient processes for the selective oxygenation of organic compounds by molecular oxygen (O2) is key for the synthesis of oxygenates. This paper discloses an atom-efficient synthesis protocol for the photo-oxygenation of 9,10-dihydroanthracene (DHA) by O2 to anthraquinone (AQ), which could achieve quantitative AQ yield (100 %) without any extra catalysts or additives under ambient temperature and pressure. A yield of 86.4 % AQ was obtained even in an air atmosphere. Furthermore, this protocol showed good compatibility for the photo-oxidation of several other compounds with similar structures to DHA. From a series of control experiments, free-radical quenching, and electron paramagnetic resonance spin-trapping results, the photo-oxygenation of DHA was probably initiated by its photoexcited state DHA*, and the latter could activate O2 to a superoxide anion radical (O2.?) through the transfer of its electron. Subsequently, this photo-oxidation was gradually dominated by the oxygenated product AQ as an active photocatalyst obtained from the oxidation of DHA by O2.?, and was accelerated with the rapid accumulation of AQ. The present photo-oxidation protocol is a good example of selective oxygenation based on the photoexcited substrate self-activated O2, which complies well with green chemistry ideals.
- Jiang, Dabo,Hu, Wenwei,Chen, Mengke,Fu, Zaihui,Su, Anqun,Yang, Bo,Mao, Feng,Zhang, Chao,Liu, Yachun,Yin, Dulin
-
p. 1785 - 1792
(2020/03/13)
-
