- Effect of the resorcin[4]arene host on the catalytic epoxidation of a Mn(III)-based resorcin[4]arene-metalloporphyrin conjugate
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The single-crystal X-ray diffraction data, binding behavior, and epoxidation reactions of the cavitand resorcin[4]arene-porphyrin conjugate are presented. Polar and nonpolar organic molecules such as pyridine and styrene were included in the cavity of res
- Al-Azemi, Talal F.,Vinodh, Mickey
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- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
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Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
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- Ni/Photoredox-Catalyzed Enantioselective Cross-Electrophile Coupling of Styrene Oxides with Aryl Iodides
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A Ni/photoredox-catalyzed enantioselective reductive coupling of styrene oxides and aryl iodides is reported. This reaction affords access to enantioenriched 2,2-diarylalcohols from racemic epoxides via a stereoconvergent mechanism. Multivariate linear regression (MVLR) analysis with 29 bioxazoline (BiOx) and biimidazoline (BiIm) ligands revealed that enantioselectivity correlates with electronic properties of the ligands, with more electron-donating ligands affording higher ee's. Experimental and computational mechanistic studies were conducted, lending support to the hypothesis that reductive elimination is enantiodetermining and the electronic character of the ligands influences the enantioselectivity by altering the position of the transition state structure along the reaction coordinate. This study demonstrates the benefits of utilizing statistical modeling as a platform for mechanistic understanding and provides new insight into an emerging class of chiral ligands for stereoconvergent Ni and Ni/photoredox cross-coupling.
- Lau, Sii Hong,Borden, Meredith A.,Steiman, Talia J.,Wang, Lucy S.,Parasram, Marvin,Doyle, Abigail G.
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supporting information
p. 15873 - 15881
(2021/10/12)
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- The first crystallographically characterised ruthenium(vi) alkylimido porphyrin competent for aerobic epoxidation and hydrogen atom abstraction
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The syntheses of [RuVI(Por)(NAd)(O)] and [RuVI(2,6-F2-TPP)(NAd)2] have been described. [RuVI(2,6-F2-TPP)(NAd)(O)] capable of catalysing aerobic epoxidation of alkenes has been characterised by X-ray crystallography with RuNAd and RuO bond distances being 1.778(5) ? and 1.760(4) ? (∠O-Ru-NAd: 174.37(19)°), respectively. Its first reduction potential is 740 mV cathodically shifted from that of [RuVI(2,6-F2-TPP)(O)2].
- Chang, Xiao-Yong,Che, Chi-Ming,Shing, Ka-Pan,Wan, Qingyun
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supporting information
p. 4428 - 4431
(2020/05/05)
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- Tri-Manganese(III) Salen-Based Cryptands: A Metal Cooperative Antioxidant Strategy that Overcomes Ischemic Stroke Damage in Vivo
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Oxidative stress is one of the hallmarks of ischemic stroke. Catalase-based (CAT) biomimetic complexes are emerging as promising therapeutic candidates that are expected to act as neuroprotectants for ischemic stroke by decreasing the damaging effects fro
- Du, Yujing,Gao, Song,Huo, Yan,Jiang, Shang-Da,Kang, Lei,Li, Cuicui,Lin, Hengyu,Ning, Yingying,Sedgwick, Adam C.,Sessler, Jonathan L.,Wang, Bing-Wu,Xue, Haozong,Yao, Yuhang,Zhang, Jun-Long
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supporting information
p. 10219 - 10227
(2020/06/27)
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Copper based coordination polymers based on metalloligands: Utilization as heterogeneous oxidation catalysts
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This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.
- Kumar, Gulshan,Hussain, Firasat,Gupta, Rajeev
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p. 16985 - 16994
(2019/01/03)
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- Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors
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Methodology for direct catalytic conversion of olefins into cyclic carbonates using peroxide and carbon dioxide under relatively mild conditions is demonstrated. The protocol utilizes packed bed flow reactors in series to couple rhenium catalyzed olefin epoxidation and aluminum catalyzed epoxide carboxylation in a single sequence.
- Sathe, Ajay A.,Nambiar, Anirudh M. K.,Rioux, Robert M.
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- Green Organocatalytic Dihydroxylation of Alkenes
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An inexpensive, green, metal-free one-pot procedure for the dihydroxylation of alkenes is described. H2O2 and 2,2,2-trifluoroacetophenone were employed as the oxidant and organocatalyst, respectively, in this highly sustainable protocol in which a variety of homoallylic alcohols, aminoalkenes, and simple alkenes were converted into the corresponding polyalcohols in good to excellent yields. This process takes advantage of an epoxidation reaction followed by an acidic treatment in which water participates in the ring opening of the in situ prepared epoxide to lead to the desired product.
- Theodorou, Alexis,Triandafillidi, Ierasia,Kokotos, Christoforos G.
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p. 1502 - 1509
(2017/04/01)
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- Potassium phosphate-catalyzed one-pot synthesis of 3-aryl-2-oxazolidinones from epoxides, amines, and atmospheric carbon dioxide
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Potassium phosphate was found to be a highly active catalyst in the three-component cycloaddition of amines, epoxides, and carbon dioxide in DMF at ambient temperature to form 3-aryl-2-oxazolidinones. Atmospheric CO2 and a broad range of amines were employed in this transformation. Aryl isocyanate and 1,2-aminoalcohol were generated in situ as key intermediates. This one-pot reaction is applicable to a variety of terminal epoxides and amines. The key advantages are high yields, simple work-up, inexpensive catalysts, and a practical ten gram-scale synthesis.
- Seo, Ue Ryung,Chung, Young Keun
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supporting information
p. 803 - 808
(2017/08/15)
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- Three powerful dinuclear metal-organic catalysts for converting CO2 into organic carbonates
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Developing efficient catalysts for converting carbon dioxide (CO2) into varied organic carbonates is an important scientific goal. By using the NH2-functionalized tripodal ligand 2-((bis(2-aminoethyl)amino)methyl)phenol (HL), three dinuclear metal-organic complexes [Zn(L)]2·2ClO4 (1), [Cu(L)]2·2ClO4·2H2O (2) and [Cd(L)]2·2ClO4 (3) have been successfully isolated and structurally characterized using single-crystal X-ray diffraction analyses. Considering the dinuclear metal centers and the NH2-functional groups in the structures, 1-3 were investigated as catalysts for converting CO2 into organic carbonates, and the results show that 1-3 exhibit an outstanding ability for converting CO2 into varied organic carbonates at atmospheric pressure (0.1 MPa). The catalytic system also displays a wide substrate scope and high catalytic activity, and the reaction mechanism has been proposed herein.
- Zhao, Dan,Liu, Xiao-Hui,Shi, Zhuang-Zhi,Zhu, Chen-Dan,Zhao, Yue,Wang, Peng,Sun, Wei-Yin
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p. 14184 - 14190
(2016/11/05)
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- One-pot epoxidation of alkenes using aerobic photoperoxidation of toluenes
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We developed an aerobic photooxidative synthesis of peroxybenzoic acids from toluenes using anthraquinone-2-carboxylic acid (AQN-2-CO2H) as a photocatalyst. We also found a one-pot epoxidation reaction of alkenes using 4-tert-butylperoxybenzoic acid produced in situ by aerobic photooxidative synthesis.
- Taguchi, Miyabi,Nagasawa, Yoshitomo,Yamaguchi, Eiji,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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supporting information
p. 230 - 232
(2015/12/31)
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- The Activation of Carboxylic Acids via Self-Assembly Asymmetric Organocatalysis: A Combined Experimental and Computational Investigation
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The heterodimerizing self-assembly between a phosphoric acid catalyst and a carboxylic acid has recently been established as a new activation mode in Br?nsted acid catalysis. In this article, we present a comprehensive mechanistic investigation on this activation principle, which eventually led to its elucidation. Detailed studies are reported, including computational investigations on the supramolecular heterodimer, kinetic studies on the catalytic cycle, and a thorough analysis of transition states by DFT calculations for the rationalization of the catalyst structure-selectivity relationship. On the basis of these investigations, we developed a kinetic resolution of racemic epoxides, which proceeds with high selectivity (up to s = 93), giving the unreacted epoxides and the corresponding protected 1,2-diols in high enantiopurity. Moreover, this approach could be advanced to an unprecedented stereodivergent resolution of racemic α-chiral carboxylic acids, thus providing access to a variety of enantiopure nonsteroidal anti-inflammatory drugs and to α-amino acid derivatives.
- Monaco, Mattia Riccardo,Fazzi, Daniele,Tsuji, Nobuya,Leutzsch, Markus,Liao, Saihu,Thiel, Walter,List, Benjamin
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supporting information
p. 14740 - 14749
(2016/11/18)
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- Catalytic Enantioselective Conversion of Epoxides to Thiiranes
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A highly efficient and enantioselective Br?nsted acid catalyzed conversion of epoxides to thiiranes has been developed. The reaction proceeds in a kinetic resolution, furnishing both epoxide and thiirane in high yields and enantiomeric purity. Heterodimer formation between the catalyst and sulfur donor affords an effective way to prevent catalyst decomposition and enables catalyst loadings as low as 0.01 mol %.
- Liao, Saihu,Leutzsch, Markus,Monaco, Mattia Riccardo,List, Benjamin
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supporting information
p. 5230 - 5233
(2016/05/19)
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- A Mn (III)-Salen catalyst and its preparation method and application
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The invention discloses a Mn(III)-Salen catalyst as well as a preparation method and application thereof. The method comprises the following steps: performing reaction on 5-bromo-3-tert-butyl salicylaldehyde and pyridine-4-boric acid as raw materials to generate pyridine salicylaldehyde derivatives; reacting the pyridine salicylaldehyde derivatives with ethylene diamine to synthesize a Salen ligand with a pyridine functional group; finally coordinating divalent manganese salt with the Salen ligand, oxidizing, evaporating an obtained reaction solution to dryness, washing by water and filtering to obtain the Mn(III)-Salen catalyst. According to the method, a reaction system is simple, a reagent is easily available and low in cost, a reaction product post-treatment process is simple, the product purity is high, and the obtained Mn(III)-Salen catalyst is stable to water and air and capable of catalyzing styrene, 4-tert-butyl styrene, indene, alpha-methyl styrene and the like in a manner of relatively high activity and selectivity to synthesize olefin epoxides.
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Paragraph 0087; 0088
(2017/02/02)
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- Manganese- and cobalt-based coordination networks as promising heterogeneous catalysts for olefin epoxidation reactions
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We demonstrate the synthesis of Mn2+- and Co2+-based coordination networks using two Co3+-based metalloligands differing by the position of the appended arylcarboxylate groups. The structural analyses reveal topologically distinct networks with pores of variable dimensions allowing facile diffusion of substrates and/or reagents. All four networks function as heterogeneous catalysts for the olefin epoxidation reactions using tert-butyl-hydroperoxide without any requirement of solvent or additive. Control and optimization experiments illustrate recyclable network-based catalysts that make them attractive candidates for the "greener" oxidation chemistry processes.
- Kumar, Girijesh,Kumar, Gulshan,Gupta, Rajeev
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p. 2603 - 2615
(2015/03/30)
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- Manganese Complexes of Pyrrole- and Indolecarboxamide Ligands: Synthesis, Structure, Electrochemistry, and Applications in Oxidative and Lewis-Acid-Assisted Catalysis
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This work shows the synthesis and structural, spectroscopic, and electrochemical properties of MnIII complexes supported with pyrrole- and indolecarboxamide ligands. In all cases, the respective ligand constitutes a N4 coordination sphere about the MnIII ion. The MnIII complexes of pyrrolecarboxamide ligands are square pyramidal with a fifth Cl atom, whereas analogous complexes of indolecarboxamide ligands are essentially square planar. Electrochemical studies reveal highly negative MnIII/II and moderately positive MnIV/III redox potentials. In situ generated Mn4+ species of the pyrrolecarboxamide ligands were characterized by absorption and electron paramagnetic resonance spectroscopy. All complexes functioned as catalysts in olefin epoxidation reactions by using PhIO as the oxo-transfer agent. All complexes also acted as Lewis acid catalysts for ring-opening reactions of assorted epoxides with various nucleophiles. We also show a one-pot, two-step epoxidation reaction followed by ring opening, which illustrates the catalytic significance of the present complexes. Importantly, MnIII complexes carrying electron-donating substituents on the ligand were found to be better catalysts.
- Yadav, Sunil,Kumar, Sushil,Gupta, Rajeev
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p. 5534 - 5544
(2015/12/01)
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- Rhodium-catalyzed transannulation of N-sulfonyl-1,2,3-triazoles and epoxides: Regioselective synthesis of substituted 3,4-dihydro-2 H-1,4-oxazines
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Rhodium-catalyzed transannulation of 1,2,3-triazoles and ring-opening reactions of epoxides is described. A number of 3,4-dihydro-2H-1,4-oxazines are obtained in moderate yields probably involving generation of α-imino rhodium(II) carbene species.
- Ma, Xueji,Pan, Shanfei,Wang, Hangxiang,Chen, Wanzhi
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supporting information
p. 4554 - 4557
(2015/02/19)
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- Mononuclear complexes of amide-based ligands containing appended functional groups: Role of secondary coordination spheres on catalysis
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Amide-based ligands H2L1, H2L2 and H2L3 containing thiazole, thiazoline and benzothiazole appended groups have been used to synthesize Zn2+ (1 and 3), Cd2+ complexes (2 and 4), and a Mn2+ complex (5). In all cases, potentially multidentate ligands create a meridional N3 coordination environment around the M(ii) ion whereas additional sites are occupied by labile nitrate ions in 1-4 and MeOH in 5. Interestingly, metal complexation caused the migration of protons from amidic N-H sites to the appended heterocyclic rings in complexes 1-4. Structural studies show that the protonated heterocyclic rings in these complexes create a hydrogen bond based cavity adjacent to the metal ion. Importantly, binding studies confirm that the substrates are bound within the complex cavity closer to the Lewis acidic metal in all complexes including the oxidation-sensitive Mn ion in complex 5. All complexes have been utilized as the reusable and heterogeneous catalysts for ring-opening reactions of assorted epoxides, cyanation reactions of various aldehydes, and epoxidation reactions of several olefins. This journal is
- Bansal, Deepak,Kumar, Gulshan,Hundal, Geeta,Gupta, Rajeev
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p. 14865 - 14875
(2015/02/19)
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- 2,2,2-Trifluoroacetophenone: An organocatalyst for an environmentally friendly epoxidation of alkenes
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A cheap, mild, fast, and environmentally friendly oxidation of olefins to the corresponding epoxides is reported using polyfluoroalkyl ketones as efficient organocatalysts. Namely, 2,2,2-trifluoroacetophenone was identified as an improved organocatalyst for the epoxidation of alkenes. Various olefins, mono-, di-, and trisubstituted, are epoxidized chemoselectively in high to quantitative yields utilizing 2-5 mol % catalyst loading and H2O 2 as the green oxidant.
- Limnios, Dimitris,Kokotos, Christoforos G.
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p. 4270 - 4276
(2014/06/09)
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- Efficient epoxidation of olefins by H2O2 catalyzed by iron "helmet" phthalocyanines
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High yields of epoxides were obtained in the oxidation of a large range of olefins using 1.2-2 equiv. of H2O2 in the presence of iron helmet phthalocyanines. The involvement of high-valent iron oxo species was evidenced using cryospray mass spectrometry.
- Skobelev, Igor Y.,Kudrik, Evgeny V.,Zalomaeva, Olga V.,Albrieux, Florian,Afanasiev, Pavel,Kholdeeva, Oxana A.,Sorokin, Alexander B.
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p. 5577 - 5579
(2013/07/25)
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- A new layered metal-organic framework as a promising heterogeneous catalyst for olefin epoxidation reactions
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A new layered MOF material [Co(Hoba)2·2H2O] (1) (H2oba = 4,4′-oxybis(benzoic acid)) has been synthesized and used as a highly recyclable heterogeneous catalyst for olefin epoxidation reactions. Both high conversion (96%) and high selectivity of epoxide products (96%) are achieved.
- Zhang, Jingming,Biradar, Ankush V.,Pramanik, Sanhita,Emge, Thomas J.,Asefa, Tewodros,Li, Jing
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supporting information; experimental part
p. 6541 - 6543
(2012/07/30)
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- Nickel-catalyzed cross-coupling of styrenyl epoxides with boronic acids
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Let's get multicatalytic! A Ni0 catalyst complexed with a biaryldialkyl monophosphine ligand facilitates C-C bond formation between styrenyl epoxides and aryl boronic acids (see scheme). X-ray analysis of a catalytically active nickel/ligand complex supports a redox pathway involving C sp 3-O bond activation. A variety of α-substituted alcohols were generated with good reaction efficiency by a multicatalytic sequence. Copyright
- Nielsen, Daniel K.,Doyle, Abigail G.
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supporting information; experimental part
p. 6056 - 6059
(2011/09/13)
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- Easy access to α-bromoketones and epoxides from vic-dibromides under aqueous conditions
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The conversion of vic-1,2 dibromides to α-bromoketones and epoxides using H2O2/dioxane and NaOH/water respectively under mild conditions has been described. Copyright Taylor & Francis Group, LLC.
- Patil, Rajendra D.,Adimurthy, Subbarayappa,Ranu, Brindaban C.
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experimental part
p. 3233 - 3239
(2010/12/24)
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- A mild catalytic oxidation system: Ruthenium porphyrin and 2,6-dichloropyridine n-oxide applied for alkene dihydroxylation
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A new method was developed to transform alkenes into three types of functional molecules, including epoxides, aldehydes and 1,2-diols by using dichlororuthenium(IV) meso-tetrakis(2,6-dichlorophenyl)porphyrin [Ru(IV)(TDCPP)Cl2] as catalyst and 2,6-dichloropyridine N-oxide (Cl2pyNO) as the oxidant, in which the 1,2-diols were afforded via "one-pot" reactions in moderate yields. Copyright
- Hu, Wen-Xiang,Li, Pei-Rong,Jiang, Gaoxi,Che, Chi-Ming,Chen, Jian
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scheme or table
p. 3190 - 3194
(2011/02/23)
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- Metal-free epoxidation of alkenes with molecular oxygen and benzaldehyde under visible light irradiation
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A new convenient metal-free oxidation protocol of a wide variety of alkenes with molecular oxygen and benzaldehyde under visible light irradiation of fluorescent lamp afforded their corresponding epoxides in 49-99% yields. Georg Thieme Verlag Stuttgart.
- Tada, Norihiro,Okubo, Hiroaki,Miura, Tsuyoshi,Itoh, Akichika
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experimental part
p. 3024 - 3026
(2010/03/03)
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- Catalytic oxidation of alkenes with a surface-bound metalloporphyrin- peptide conjugate
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A novel surface-bound metalloporphyrin-peptide conjugate was prepared and used to catalytically oxidize alkenes in the presence of iodosylbenzene. The catalyst was found to oxidize a number of alkene substrates in good yield under a variety of reaction conditions. Comparison to control experiments using surface-bound Mn(III)tetraphenylporphyrin showed differences in oxidation yields and ratios of oxidized products. Substrate competition experiments demonstrated the ability of the conjugate catalyst to discriminate between substrates on the basis of size. Both results suggest oxidative catalysis occurred between the porphyrin ring and the peptide chain with the peptide influencing the outcome of the reaction in accord with the catalyst design.
- Geier III, G. Richard,Sasaki, Tomikazu
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p. 1859 - 1870
(2007/10/03)
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- A Halide-Free Method for Olefin Epoxidation with 30% Hydrogen Peroxide
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A catalytic system consisting of sodium tungstate dihydrate, (aminomethyl) phosphonic acid, and methyltrioctylammonium Hydrogensulfate, effects the epoxidation of olefins using 30% hydrogen peroxide with a substrate-to-catalyst molar ratio of 50 - 500. The reaction proceeds in high yield without solvents, or, alternatively, with added toluene under entirely halide-free conditions. Lipophilic ammonium hydrogensulfate, which replaces the conventional chloride, and an (α-aminoalkyl)phosphonic acid are crucial for the high reactivity. This method is operationally simple, environmentally benign, and much more economical than the oxidation with m-chloroperbenzoic acid, allowing for a large-scale preparation of epoxides. Various substrates including terminal olefins, 1,1- and 1,2-disubstituted olefins, cyclic olefins, and tri- and tetrasubstituted olefins as well as allylic alcohols, esters, α,β-unsaturated ketones, and ethers can be epoxidized in high yield. The scope and limitations of this new reaction system are discussed.
- Sato, Kazuhiko,Aoki, Masao,Ogawa, Masami,Hashimoto, Tadashi,Panyella, David,Noyori, Ryoji
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p. 905 - 915
(2007/10/03)
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