- Oxidation of alcohols to aldehydes and ketones using TBHP as an oxidant over LaMO3 (M = Cr, Mn, Co, Ni, Fe) perovskites
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Oxidation of a wide variety of structurally and electronically diverse primary and secondary alcohols to aldehydes and ketones was carried out using a novel catalytic system of LaCrO3 and tert-butyl hydroperoxide (TBHP) under solvent-free conditions. The methodology afforded the desired carbonyl compounds in good to excellent yields, and the catalyst can be reused several times with no significant loss in activity. Copyright Taylor & Francis Group, LLC.
- Singh, Savita J.,Jayaram, Radha V.
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- Oxidation of alcohols with catalytic amounts of IBX
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Herein we present a catalytic IBX-based method for the oxidation of alcohols. Using this system a variety of benzylic alcohols were transformed to aldehydes in good yields whereas secondary alcohols were easily converted to ketones. Primary aliphatic alcohols were oxidised to the corresponding carboxylic acids. 2-lodobenzoic acid can also be used instead of IBX. Georg Thieme Verlag Stuttgart.
- Schulze, Agnes,Giannis, Athanassios
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- Chromium trioxide on H-Y zeolite: Rapid oxidation of alcohols to carbonyl compounds in solventless system using microwaves
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In an environmentally benign solventless system, alcohols are rapidly oxidized to carbonyl compounds using HY-zeolite supported chromium trioxide as an oxidant under microwave irradiation.
- Mirza-Aghayan, Maryam,Heravi, Majid M.
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- Intramolecular hydrogen transfer reaction: Menthon from isopulegol
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The flavor menthon (isomeric mixture of (-)-menthon and (+)-isomenthon) was obtained in good yields and selectivities by a solventless ruthenium catalyzed isomerization of the homoallylic alcohol (-)-isopulegol. In contrast to most previous assumptions on such isomerization reactions, this reaction follows an intermolecular pathway, with menthol and pulegon being the central intermediates in this transformation.
- Schaub, Thomas,Ruedenauer, Stefan,Weis, Martine
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- Oxidation of secondary alcohols using molecular oxygen and benzaldehyde in the absence of metal catalysts
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A simple and convenient method for the oxidation of secondary alcohols using molecular oxygen, benzaldehyde in 1,2-dichloroethane in the absence of metal catalysts is described for the first time.
- Choudary, Boyapati M.,Sudha, Yepuri
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- Oxidation of Benzylic and Secondary Alcohols to Carbonyl Compounds by NaBrO3-NH4Cl Reagent in Aqueous Acetonitrile
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NaBrO3 combined with NH4Cl is found to be an efficient reagent for the conversion, in aqueous acetonitrile and under mild conditions, of benzylic and secondary alcohols into aldehydes and ketones, respectively.
- Shaabani, Ahmad,Ameri, Majid
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- Cu/SiO2: An improved catalyst for the chemoselective hydrogenation of α,β-unsaturated ketones
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Cu/SiO2 can be conveniently used for the quantitative hydrogenation of conjugated enones to saturated ketones, also when another olefinic bond is present in the molecule, under very mild conditions. Molecular H2 or 2-propanol can be used as hydrogen source.
- Ravasio, Nicoletta,Antenori, Marisa,Gargano, Michele,Mastrorilli, Piero
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- Preparation and Use of Tetra-n-butylammonium Per-ruthenate (TBAP reagent) and Tetra-n-propylammonium Per-ruthenate (TPAP reagent) as New Catalytic Oxidants for Alcohols
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Tetra-n-butylammonium per-ruthenate (Bun4N)(RuO4) and tetra-n-propylammonium per-ruthenate (Prn4N)(RuO4), with N-methylmorpholine N-oxide, function as mild catalitic oxidants for the high yield conversion of alcohols to aldehydes and ketones and are competitive with more conventional reagents.
- Griffith, William P.,Ley, Steven V.,Whitcombe, Gwynne P.,White, Andrew D.
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- Engineering the "missing Link" in Biosynthetic (-)-Menthol Production: Bacterial Isopulegone Isomerase
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The realization of a synthetic biology approach to microbial (1R,2S,5R)-(-)-menthol (1) production relies on the identification of a gene encoding an isopulegone isomerase (IPGI), the only enzyme in the Mentha piperita biosynthetic pathway as yet unidentified. We demonstrate that Δ5-3-ketosteroid isomerase (KSI) from Pseudomonas putida can act as an IPGI, producing (R)-(+)-pulegone ((R)-2) from (+)-cis-isopulegone (3). Using a robotics-driven semirational design strategy, we identified a key KSI variant encoding four active site mutations, which confer a 4.3-fold increase in activity over the wild-type enzyme. This was assisted by the generation of crystal structures of four KSI variants, combined with molecular modeling of 3 binding to identify key active site residue targets. The KSI variant was demonstrated to function efficiently within cascade biocatalytic reactions with downstream Mentha enzymes pulegone reductase and (-)-menthone:(-)-menthol reductase to generate 1 from 3. This study introduces the use of a recombinant IPGI, engineered to function efficiently within a biosynthetic pathway for the production of 1 in microorganisms.
- Currin, Andrew,Dunstan, Mark S.,Johannissen, Linus O.,Hollywood, Katherine A.,Vinaixa, Maria,Jervis, Adrian J.,Swainston, Neil,Rattray, Nicholas J. W.,Gardiner, John M.,Kell, Douglas B.,Takano, Eriko,Toogood, Helen S.,Scrutton, Nigel S.
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- OXYDATION D'ALCOOLS PAR L'ANHYDRIDE CHROMIQUE DANS LES CONDITIONS DU TRANSFERT DE PHASE SOLIDE-LIQUIDE.
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Catalytic amounts quaternary ammonium salts afforded efficient oxidation of alcohols by chromium trioxide at room temperature in organic solvents.
- Gelbard, Georges,Brunelet, Thierry,Jouitteau, Catherine
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- Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds by Catecholborane
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α,β-Unsaturated ketones which can readily adopt an s-cis conformation undergo conjugate reduction by catecholborane at room temperature. α,β-Unsaturated imides, esters, and amides are unreactive under the same conditions.However, catalytic quantities of Rh(PPh3)3Cl greatly accelerate the 1,4-addition process, effecting conjugate reduction of these substrates by catecholborane at -20 deg C.The resulting boron enolates may be reacted with electrophiles to provide functionalized products.
- Evans, David A.,Fu, Gregory C.
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- Pd(II)-hydrotalcite-catalyzed selective oxidation of alcohols using molecular oxygen
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A novel heterogenized Pd catalyst, Pd supported by hydrotalcite [Pd(II)-hydrotalcite], was synthesized by a simple operation from commercially available hydrotalcite, Pd(OAc)2 and pyridine. The catalyst was effective for the oxidation of a wide range of alcohols using molecular oxygen as a sole oxidant. With this catalytic system, various alcohols were readily converted to the corresponding aldehydes or ketones selectively in high to excellent yields. Sterically less hindered substrates were converted to the corresponding ketones much faster than the hindered ones. For example, cyclohexanol was converted to cyclohexanone in 79% yield for 15 hr, while larger-sized cyclic alcohols were oxidized to the corresponding ketones only in 32-77% yields in the same reaction time. The catalyst was also applicable to the oxidation of unsaturated alcohols such as geraniol and nerol without any isomerization of an alkenic part. Modified Pd(II)-hydrotalcite [Pd(II)-hydrotalcite(m)] could be reused several times while keeping its activity.
- Uemura,Kakiuchi,Nishimura,Inoue
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- Photochemical Transformations with Iodine Azide after Release from an Ion-Exchange Resin
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This report discloses the photochemical homolytic cleavage of iodine azide after its formation following release from polymer-bound bisazido iodate(I) anions. A series of radical reactions are reported including the 1,2-functionlization of alkenes and the unprecedented chemoselective oxidation of secondary alcohols in the presence of primary alcohols.
- Dr?ger, Gerald,K?sel, Teresa,Kirschning, Andreas,Schulz, G?ran
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- 1-Methyl-3-butylimidazolium decatungstate in ionic liquid: An efficient catalyst for the oxidation of alcohols
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An excellent system for the selective oxidation of benzylic and secondary alcohols with hydrogen peroxide catalyzed by 1-methyl-3-butylimidazolium decatungstate in [bmim][BF4] ionic liquid is described. The catalytic system is reusable and products are obtained in excellent yield under environmentally benign conditions.
- Chhikara, Bhupender S.,Tehlan, Sarita,Kumar, Anil
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- Desilylative oxidation of alkyl trimethylsilyl ethers with pyridinium fluorochromate
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Direct conversion of alkyl trimethylsilyl ethers to carbonyl compounds is accomplished using PFC in dichloromethane at room temperature. For a similar oxidation of t-butyldimethylsilyl ethers the PCC-n-Bu4NF combination may be employed.
- Ho, Tse-Lok,Jana, Gour Hari
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- ULTRASONICALLY IMPROVED REDUCTIVE PROPERTIES OF AN AQUEOUS Zn-NiCl2 SYSTEM - 1 SELECTIVE REDUCTION OF α,β-UNSATURATED CARBONYL COMPOUNDS
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Conjugate addition of several compounds is obtained with good to excellent yield in an aqueous medium using a reagent constituted by zinc dust and nickel chloride(9-1).Ultrasounds are shown to improve the yields and reaction rates.
- Petrier, Christian,Luche, Jean-Louis
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- Novel Method of Oxidation by a Polymeric reagent Electrochemically Generated and Recycled in Situ. Facile Oxidation of Alcohols.
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A polymeric reagent electrochemically generated from crosslinked poly-4-vinylpyridine hydrobromide (1) was found to oxidize secondary alcohols to give the corresponding ketones in the absence of electric current.The exhausted polymeric reagent was regenerated by electrochemical oxidation.Thus a mild method of oxidation was developed which involved an electrochemical process in the presence of 1.Secondary alcohols were oxidized by this method to give the corresponding ketones in high yields, and hydrogen was formed quantitatively as a second product.Since the exhausted polymeric reagent is regenerated by continuous electrochemical oxidation in situ, only a catalytic amount of 1 (based on the alcohol) is required for the reaction, and the method does not consume any chemical oxidant and does not produce any contaminating reduced product.The efficiency of the electric current was very high, and only a slight excess of electricity was required to obtain the ketones in satisfactory yields.This method may remove defects of conventional electroorganic processes such as difficulty in separation and recovery of the electrolytes.
- Yoshida, Jun-ichi,Nakai, Ryoichi,Kawabata, Nariyoshi
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- Novel Vanadium-Catalyzed Oxidation of Alcohols to Aldehydes and Ketones under Atmospheric Oxygen
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(Matrix presented) Oxidation of alcohols to aldehydes and ketones has been studied in high yields using atmospheric oxygen and a catalytic amount of V 2O5 in toluene under heating (ca. 100°C). Secondary alcohols can be chemoselectively converted into ketones in the presence of primary hydroxy groups.
- Velusamy, Subbarayan,Punniyamurthy
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- FACILE HOMOGENEOUS HYDROGENATIONS OF HINDERED OLEFINS WITH PF6
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The title complex readily hydrogenates a number of hindered steroidal olefin groups from the α face, without reducing ketone carbonyl groups, carbon-halogen bonds or cyclopropane rings.
- Suggs, J. William,Cox. S. D.,Crabtree, Robert H.,Quirk, Jennifer M.
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- Transition-metal- and organic-solvent-free: A highly efficient anaerobic process for selective oxidation of alcohols to aldehydes and ketones in water
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A new system, I2-KI-K2CO3-H2O, selectively oxidized alcohols to aldehydes and ketones under anaerobic condition in water at 90°C with excellent yields. The process is green, mild and inexpensive. The Royal Society of Chemistry 2005.
- Gogoi, Pranjal,Konwar, Dilip
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- Efficient solvent-free iron(III) catalyzed oxidation of alcohols by hydrogen peroxide
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Selective oxidation of secondary and benzylic alcohols was efficiently accomplished by H2O2 under solvent-free condition catalyzed by FeBr3. Secondary alcohols are selectively oxidized even in the presence of primary ones.
- Martín, Sandra E.,Garrone, Analía
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- Efficient ruthenium-catalyzed aerobic oxidation of alcohols using a biomimetic coupled catalytic system
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Efficient aerobic oxidation of alcohols was developed via a biomimetic catalytic system. The principle for this aerobic oxidation is reminiscent of biological oxidation of alcohols via the respiratory chain and involves selective electron/proton transfer. A substrate-selective catalyst (ruthenium complex 1) dehydrogenates the alcohol, and the hydrogens abstracted are transferred to an electron-rich quinone (4b). The hydroquinone thus formed is continuously reoxidized by air with the aid of an oxygen-activating Co-salen type complex (6). Most alcohols are oxidized to ketones in high yield and selectivity within 1-2 h, and the catalytic system tolerates a wide range of O2 concentrations without being deactivated. Compared to other ruthenium-catalyzed aerobic oxidations this new catalytic system has high turnover frequency (TOF).
- Csjernyik, Gabor,Ell, Alida H.,Fadini, Luca,Pugin, Benoit,Baeckvall, Jan-E.
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- Synthesis of enantiopure triols from racemic Baylis?Hillman adducts using a diastereoselective peroxidation reaction
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Using a chiral (?)-menthone auxiliary, enantiopure cyclic derivatives of Baylis?Hillman adducts were synthesized. A diastereoselective peroxidation reaction was used to introduce an oxygen atom and establish another stereocenter. The resulting products could be elaborated by employing a one-flask reduction?acetylation protocol followed by a diastereoselective nucleophilic substitution reaction. Removal of the (?)-menthone auxiliary provided an enantiopure triol with a structure related to naturally occurring polyols.
- Woerpel,Zuckerman, Dylan S.
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- Direct oxidative deprotection of tetrahydropyranyl ethers using hexamethylenetetramine-bromine supported onto silica gel under microwave irradiation in solventless system
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Primary and secondary tetrahydropyranyl ethers (THP ethers) are converted to their corresponding carbonyl compounds efficiently using hexamethylene- tetramine-bromine supported onto silica gel under microwave irradiation in solvent-free conditions.
- Dehkordi, Mahboobeh Behnam,Heravi, Majid M.,Ziafati, Ahmad,Khosrofar, Parviz,Ghassemzadeh, Mitra
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- CERIUM CATALYZED SELECTIVE OXIDATION OF SECONDARY ALCOHOLS IN THE PRESENCE OF PRIMARY ONES
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The combination of (NH4)2Ce(NO3)6-NaBrO3 or Ce(SO4)2.2H2SO4-NaBrO3 has been found to be effective for the title selective oxidation.
- Tomioka, Hiroki,Oshima, Koichiro,Nozaki, Hitosi
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- A facile deprotection of dithioacetals by FeCl3/KI
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Carbonyl compounds were regenerated from corresponding dithioacetals via refluxing with FeCl3/KI and methanol as a solvent.
- Chavan, Subhash P.,Soni, Priti B.,Kale, Ramesh R.,Pasupathy
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- Oxidative Deprotection of Tetrahydropyranyl Ethers to Carbonyl Compounds with Montmorillonite K-10 Supported Bis(trimethylsilyl) Chromate under Non-aqueous Conditions
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A variety of tetrahydropyranyl ethers are oxidized to the corresponding carbonyl compounds in excellent yields by montmorillonite K-10 supported bis(trimethylsilyl) chromate in dichloromethane at room temperature.
- Heravi, Majid M.,Ajami, Dariush
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- HOF·CH3CN, made directly from F2 and water, as an ecologically friendly oxidizing reagent
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The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.
- Rozen, Shlomo,Bareket, Yifat,Kol, Moshe
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- New biobased tetrabutylphosphonium ionic liquids: Synthesis, characterization and use as a solvent or co-solvent for mild and greener Pd-catalyzed hydrogenation processes
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Phosphonium-based Ionic Liquids (PhosILs) with natural organic derived anions (l-lactate, l-tartrate, malonate, succinate, l-malate, pyruvate, d-glucuronate, d-galacturonate, ferulate, p-coumarate) were easily prepared by acid-base method from tetrabutylphosphonium hydroxide and an excess of the corresponding acid with good yields. Their characterization was realized through classical NMR, IR and elemental analysis techniques; their viscosity and ATG parameters were also determined. These ionic liquids showed good performance and recyclability in the selective Pd-catalyzed hydrogenation of alkenes, polyenes like linoleic acid and enantioselective hydrogenation of unsaturated ketones such as isophorone at room temperature under atmospheric H2 pressure. Furthermore, NMR studies leading to computational calculations were performed to establish easily the composition of the resulting mixture obtained through the hydrogenation of linoleic acid.
- Hayouni, Safa,Robert, Anthony,Ferlin, Nadège,Amri, Hassen,Bouquillon, Sandrine
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p. 113583 - 113595
(2016)
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- Oxidative Cleavage of Methyl Ethers Using the HOF*CH3CN Complex
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HOF*CH3CN complex, made easily by bubbling fluorine diluted with nitrogen through aqueous acetonitrile, proved to be a suitable oxidizer for various methyl ethers.Secondary ethers are oxidized to ketones and even to lactones via Baeyer-Villiger type of oxidation.The reaction is ionic, and the reagent's electrophilic oxygen attacks the relatively electron rich C-H bond α to the ether moiety.It was found that the more sterically hindered is the C-H bond in question, the slower the reaction.In cases where this bond is an electron poor one as in benzoin methyl ether (9), no reaction takes place.When labeled H(18)OF*CH3CN is used on a (16)O methyl ether, the resulting ketone possesses only the heavier oxygen isotope.Primary methyl ethers are somewhat slower to react, but they too were oxidized in very good yields to acids via the corresponding aldehydes.
- Rozen, Shlomo,Dayan, Sharon,Bareket, Yifat
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- Oxidation of Secondary Alcohols over Hydrous Zirconium(IV) Oxide
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The oxidation of secondary alcohols with ketones was carried out by catalysis with hydrous zirconium(IV) oxide.In the batch reaction system, the oxidation proceeded efficiently to give the corresponding ketones, except for some secondary alcohols.On the other hand, all of the secondary alcohols were efficiently converted to the corresponding ketones in the flow oxidation system.The influence of the hydrogen acceptor on the oxidation rate was investigated by the use of several ketones, and the oxidation rate was influenced by the electron density and steric hindrance around the carbonyl group.The dependence on the reaction temperature was also investigated in the flow reaction system.
- Kuno, Hideyuki,Takahashi, Kyoko,Shibagaki, Makoto,Shimazaki, Kazuko,Matsushita, Hajime
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- Nicotinamide-dependent Ene reductases as alternative biocatalysts for the reduction of activated alkenes
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Four NAD(P)H-dependent non-flavin ene reductases have been investigated for their ability to reduce activated C=C bonds in an asymmetric fashion by using 20 structurally diverse substrates. In comparison with flavin-dependent Old Yellow Enzyme homologues, a higher degree of electronic activation was required, because the best activities were obtained with enals and nitroalkenes rather than enones and carboxylic esters. Although FaEO from Fragaria x ananassa (strawberry) and its homologue SlEO from Solanum lycopersicum (tomato) exhibited a narrow substrate spectrum, progesterone 5β-reductase (At5β-StR) from Arabidopsis thaliana (thale cress) and leukotriene B4 12-hydroxydehydrogenase (LTB4DH/PGR) from Rattus norvegicus (rat) appear to be promising candidates, in particular for the asymmetric bioreduction of open-chain enals, nitroalkenes and α,β-unsaturated γ-butyrolactones. Competing nitro reduction and non-enzymatic Weitz-Scheffer epoxidation were largely suppressed. Electronically activated alkenes have been stereoselectively reduced by using a single-enzyme-cofactor system employing nicotinamide-dependent non-flavin ene reductases. Copyright
- Durchschein, Katharina,Wallner, Silvia,MacHeroux, Peter,Schwab, Wilfried,Winkler, Thorsten,Kreis, Wolfgang,Faber, Kurt
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- Menthylamine synthesis via gold-catalyzed hydrogenation of menthone oxime
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In the current work gold nanoparticles supported on oxides (MgO, Al2O3, ZrO2, TiO2) were used for menthylamine synthesis via menthone oxime hydrogenation. An increase of the gold nanoparticles size and application of metal oxides with a strong basic character such as magnesia favored deoximation to menthone. Au/Al2O3 catalyst with the gold nanoparticles size of 2.0 nm afforded high catalytic activity and selectivity to menthylamine. The reaction kinetics including stereoselectivity to the reaction products and recyclability of the catalyst was studied using Au/Al2O3 in the temperature range 90?110 °C under hydrogen pressure of 5.5–7.5 bar. The catalytic behavior was influenced by the solvent nature, with higher selectivity to desired amine achieved using methanol. The reaction rate was pressure independent, while has first order with respect to menthone oxime concentration. Stereoselectivity to menthylamines and menthones was independent on the reaction temperature and the hydrogen pressure.
- Demidova, Yu. S.,Mozhaitsev, E. S.,Murzin, D. Yu.,Nefedov, A. A.,Salakhutdinov, N. F.,Saraev, A. A.,Simakov, A.,Simakova, I. L.,Suslov, E. V.,Volcho, K. P.
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- A versatile method for the hydrogen peroxide oxidation of alcohols using PTC condition in tert-butanol
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An efficient protocol for the oxidation of secondary and primary alcohols to the corresponding ketones and aldehydes and/or carboxylic acids using hydrogen peroxide as oxidant is described. A quasi-homogenous reaction system was obtained by t-butanol as solvent to achieve high yield of the product in short time.
- Chhikara, Bhupender S.,Chandra, Ramesh,Tandon, Vibha
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- The Crystal Structures of 22> and 2 and Their Use as Catalytic Oxidants
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The new trinuclear heteropolyperoxo complexes 22> (R = Ph, M = Mo 1 or W 2) have been isolated and the crystal structure of the molybdenum complex is reported.A series of analogous molybdenum complexes (R = Me, Et, n-Bu, or t-Bu; M = Mo) have also been synthesised and characterised.The use of these compounds as catalysts for the epoxidation of alkenes, oxidation of alcohols and of tertiary amines with hydrogen peroxide as cooxidant has been studied, and complex 2 is shown to be particularly effective for such oxidations.The crystal structure of the new tetranuclear isopolyperoxo species 2 3 is also reported and its properties as a catalyst for alkene epoxidation with hydrogen peroxide as cooxidant studied.
- Griffith, William P.,Parkin, Bernadeta C.,White, Andrew J. P.,Williams, David J.
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- Preparation and reactivity of 1,3,5,7-tetrakis[4-(diacetoxyiodo)phenyl] adamantane, a recyclable hypervalent iodine(III) reagent
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A wide range of oxidative reactions are mediated by novel, nonpolymeric, and recyclable hypervalent IIII reagents (e.g. 2). In all cases, tetraiodide 1 was recovered nearly quantitatively in pure form after a simple workup. Reoxidation of 1 to
- Tohma, Hirofumi,Maruyama, Akinobu,Maeda, Akihisa,Maegawa, Tomohiro,Dohi, Toshifumi,Shiro, Motoo,Morita, Tetsuichiro,Kita, Yasuyuki
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- Oxidation of alcohols to aldehydes and ketones by HIO3 in presence of NaHSO4·H2O
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Different types of alcohols are efficiently converted to their corresponding aldehyds and ketones with HIO3 in presence of NaHSO4·H2O. All reaction was performed in CH 3CN medium in good to high yields.
- Khademian, Mohsen,Khademian, Maryam,Rahimnejad, Mostafa,Mokhtarian, Nader
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- Zeofen: A user-friendly catalyst for oxidative cleavage of tetrahydropyranyl ethers under non-aqueous conditions
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Primary and secondary tetrahydropyranyl ethers are efficiently converted to carbonyl compounds in excellent yields by zeofen under non-aqueous conditions.
- Mohajerani,Heravi,Ajami
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- A Novel Hexanuclear Heteropolyperoxo Oxidation Catalyst: Preparation, X-Ray Crystal Structure and Reactions of 3W6O13(O2)4(OH)2(OH2)>*4H2O
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The crystal structure of the title compound, 1, reveals the presence of two distinct types of tungsten atom in which the four bearing peroxo groups have distorted pentagonal-bipyramidal geometries and the remaining two are octahedral; 1 is an effective catalyst for monoalkene epoxidation, and the oxidation of primary and secondary alcohols, with H2O2 as co-oxidant.
- Griffith, William P.,Parkin, Bernardeta C.,White, Andrew J. P.,Williams, David J.
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- Investigations into the selective oxidation of vicinal diols to α-hydroxy ketones with the NaBrO3/NaHSO3 reagent: PH dependence, stoichiometry, substrates and origin of selectivity
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The NaBrO3/NaHSO3 reagent is one of the few oxidizing agents that chemoselectively oxidizes vicinal diols to α-hydroxy ketones with little overoxidation to the corresponding vicinal-dione or dicarboxylic acid. Oxidation reactions performed with this reagent showed strong pH dependence. cis-Vicinal diols reacted faster than trans-vicinal diols to the α-hydroxy ketone product. Hydroxy functional groups at axial ring positions were more readily oxidized than equatorial hydroxy groups. The application of the NaBrO3/NaHSO3 reagent for the chemoselective oxidation of vicinal diols was limited to simple systems and failed with more complex monosaccharide compounds probably due to acid catalyzed dehydrogenation reactions. Despite the simple reaction set-up and good selectivity towards the α-hydroxy ketone product, the actual oxidation reaction mechanism is highly complex and postulated to involve at least six different equilibria with a plethora of bromine containing species. A possible oxidation reaction mechanism is discussed.
- Bierenstiel, Matthias,D'Hondt, Paul J.,Schlaf, Marcel
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- Cucurbit[5]uril-mediated electrochemical hydrogenation of α,β-unsaturated ketones
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The potential of cucurbit[5]uril to be used as inverse phase transfer catalyst in electrocatalytic hydrogenation of α,β-unsaturated ketones is illustrated. The interaction behavior among isophorone and cucurbit[5]uril was also investigated using cyclic voltammetry and UV/vis absorption spectroscopy. The results concerning to both techniques revealed an enhancement in the intensity of the absorption peak and also in the current cathodic peak of isophorone in presence of cucurbit[5]uril. This achievement is related to the increase of the isophorone solubility in the medium being an indicative of a host-guest complex formation. The electrochemical hydrogenation of isophorone using cucurbit[5]uril was more efficient than others well-stablish methodologies. Regarding to (R)-(+)-pulegone and (S)-(+)-carvone, the use of cucurbit[5]uril leads to an increase of 17% and 9%, on average, respectively, in the yields when compared to the control reaction. The efficiency of selective C=O bond hydrogenation of 1-acetyl-1-cyclohexene was evaluated. The presence of cucurbit[5]uril increased by 12% the hydrogenations yields of 1-acetyl-1-cyclohexene when compared to the control reaction. In this sense, these results open up an opportunity to carry out electrocatalytic reactions within the cucurbit[5]uril environment.
- Sales, Ayrlane,de Oliveira e Castro, Isabela Andrade,de Menezes, Frederico Duarte,Selva, Thiago Matheus Guimar?es,Vilar, Márcio
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- Acceleration of bromide mediated benzoylperoxide oxidations of secondary alcohols in aqueous organic solvents
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The efficiency of the bromide mediated benzoylperoxide oxidation of 2° alcohols to ketones was greatly improved by the addition of water. The aqueous oxidation protocol allows also the direct use of off-the-shelf benzoylperoxide reagent without an otherwise necessary and potentially dangerous drying procedure. The oxidation of cyclopentanol, cyclohexanol, 1-phenyl-ethanol and three menthol isomers occurred in good to excellent yields. The oxidation reaction tolerated N,N-dimethylacetamide (DMA) as the solvent, which resulted in a slightly lower oxidation rate than acetonitrile. Chemoselective oxidation of vicinal diols to α-hydroxy ketones did not succeed under the aqueous organic conditions employed as over-oxidation and bromination side-reactions were observed. The impact of water content, solvent, oxidant source and type of alcohol substrates employed was investigated.
- Youm, Jennessa Ji Youn,Schlaf, Marcel,Bierenstiel, Matthias
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- Oxidative deprotection of trimethylsilyl ethers with hexamethylenetetramine-bromine supported onto silica gel under microwave irradiation in solventless system
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Hexamethylenetetramine-bromine supported onto silica gel rapidly converts trimethylsilyl ethers to their corresponding carbonyl compounds under microwave irradiation in solventless system.
- Dehkordi, Mahboobeh Behnam,Heravi, Mojid M.,Khosrofar, Parviz,Ziafat, Ahmad,Ghassemzadeh, Mitra
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- A New Epoxidation Catalyst: the Reactivity and X-Ray Crystal Structure of >*1.5H2O (bipy = 2,2'-bipyridine)
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The crystal structure of >*1.5H2O 1 is reported: with NaIO4 or NBun4IO4 as cooxidant it is an efficient catalyst for alkene epoxidations under mild conditions; it also oxidises primary alcohols to aldehydes and secondary alcohols to ketones.
- Bailey, Alan J.,Griffith, William P.,White, Andrew J. P.,Williams, David J.
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- Quinoxalinium fluorochromate (QxFC): A new and efficient reagent for the oxidation of alcohols in solution, under solvent-free conditions and microwave irradiation
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The new mild oxidizing agent, quinoxalinium fluorochromate (QxFC), has been easily prepared by reacting quinoxaline with an aqueous solution of CrO 3 and HF. This reagent is suitable for oxidizing various primary and secondary alcohols to their corresponding carbonyl compounds and anthracene to antraquinone. The reactions were carried out in solution, under solvent-free conditions and microwave irradiation. The results show that the rates of the reactions and the yields are usually highest under microwave irradiation. Copyright Taylor & Francis Group, LLC.
- Sendil, Kivilcim,Oezguen, Beytiye
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Read Online
- One pot deprotective oxidation of O-allyl ethers using 70% tert-Butyl Hydroperoxide and catalytic CrO3
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Deprotection of O-allyl ether and in situ oxidation of the liberated free hydroxy group to carbonyl functionality is achieved in one pot using 70% tert-Butyl Hydroperoxide and catalytic CrO3. Other sensitive groups viz., -OTHP, -OTBDMS and -OMOM ethers survive under the reaction conditions.
- Chandrasekhar,Mohanty, Pradyumna K.,Ramachander
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Read Online
- A TEMPO-Functionalized Ordered Mesoporous Polymer as a Highly Active and Reusable Organocatalyst
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The properties of high stability, periodic porosity, and tunable nature of ordered mesoporous polymers make these materials ideal catalytic nanoreactors. However, their application in organocatalysis has been rarely explored. We report herein for the first time the incorporation of a versatile organocatalyst, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), into the pores of an FDU-type mesoporous polymer via a pore surface engineering strategy. The resulting FDU-15-TEMPO possesses a highly ordered mesoporous organic framework and enhanced stability, and shows excellent catalytic activity in the selective oxidation of alcohols and aerobic oxidative synthesis of 2-substituted benzoxazoles, benzimidazoles and benzothiazoles. Moreover, the catalyst can be easily recovered and reused for up to 7 consecutive cycles.
- Guo, Ying,Wang, Wei David,Li, Shengyu,Zhu, Yin,Wang, Xiaoyu,Liu, Xiao,Zhang, Yuan
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supporting information
p. 3689 - 3694
(2021/09/29)
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- Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
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A copper-based magnetic nanocatalyst has been prepared by co-precipitation method and characterized by FESEM, EDS, TEM, XRD, XRF, ICP–OES, FTIR, and BET analysis. This new nanocatalyst displays a good activity toward the aerobic oxidation of a wide range of alcohols in water. Moreover, it is recyclable up to five following runs by simple filtration without any significant loss of its catalytic activity.
- Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
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p. 2527 - 2538
(2021/03/24)
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- Selective C-C Bond Cleavage of Cycloalkanones by NaNO2/HCl
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A novel selective fragmentation of cycloalkanones by NaNO2/HCl has been established. The C-C bond cleavage reaction proceeds smoothly under mild conditions, selectively affording versatile keto acids or oxime acids. The methodology can streamline the synthesis of valuable chiral molecules and isocoumarins from readily available feedstocks.
- He, Tianyu,Chen, Dengfeng,Qian, Shencheng,Zheng, Yu,Huang, Shenlin
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supporting information
p. 6525 - 6529
(2021/09/02)
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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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- A Mild, General, Metal-Free Method for Desulfurization of Thiols and Disulfides Induced by Visible-Light
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A visible-light-induced metal-free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.
- Qiu, Wenting,Shi, Shuai,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
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supporting information
p. 1255 - 1258
(2021/05/05)
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- Design and synthesis of a versatile cooperative catalytic aerobic oxidation system with co-immobilization of palladium nanoparticles and laccase into the cavities of MCF
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We have designed a versatile reusable cooperative catalyst oxidation system, consisting of palladium nanoparticles and laccase with unprecedented reactivity. This biohybrid catalyst was synthesized by the stepwise immobilization of laccase as an enzyme and Pd as a nanometallic component into the same cavity of siliceous mesocellular foams (MCF). MCF and nanobiohybrid catalyst were characterized by BET, SAXS, SEM, EDX elemental mapping, ICP-OES, TEM, TGA, FT-IR, and XPS techniques and the stepwise immobilization of laccase enzyme and Pd onto MCF was evaluated through several compelling electrochemical studies. The present catalytic system exhibits high activity toward (i) aerobic oxidation of alcohols to the corresponding carbonyl compounds, (ii) aerobic oxidation of cyclohexanol and cyclohexanone to phenol and (iii) aerobic dehydrogenation of important N-heteocyclic compounds (tetrahydro quinazolines, quinazolonones, pyrazolines and 1,4-diydropyridines) in the presence of catalytic amount of hydroquinone (HQ) as mediator in phosphate buffer (0.1 M, pH 4.5, 4 mL)/THF (4%, 1 mL) as solvent under mild conditions. The immobilization of both oxygen-activating catalyst (laccase) and oxidizing catalyst (Pd) onto the same support makes the present catalyst system superior to other currently available heterogeneous palladium based catalytic aerobic oxidation systems.
- Moradi, Sirvan,Shokri, Zahra,Ghorashi, Nadya,Navaee, Aso,Rostami, Amin
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p. 305 - 319
(2020/01/21)
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- Photochemical oxidation of benzylic primary and secondary alcohols utilizing air as the oxidant
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A mild and green photochemical protocol for the oxidation of alcohols to aldehydes and ketones was developed. Utilizing thioxanthenone as the photocatalyst, molecular oxygen from air as the oxidant and cheap household lamps or sunlight as the light source, a variety of primary and secondary alcohols were converted into the corresponding aldehydes or ketones in low to excellent yields. The reaction mechanism was extensively studied.
- Nikitas, Nikolaos F.,Tzaras, Dimitrios Ioannis,Triandafillidi, Ierasia,Kokotos, Christoforos G.
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supporting information
p. 471 - 477
(2020/02/13)
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- IBX-TfOH mediated oxidation of alcohols to aldehydes and ketones under mild reaction conditions
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An efficient, practical and facile procedure has been developed for the oxidation of primary and secondary alcohols using IBX-TfOH catalytic system in 1,4-dioxane at ambient temperature. The reaction affords quantitative yields of the corresponding carbonyl compounds without the formation of over oxidized products. The present synthetic protocol is compatible with a variety of substrates having arene, heteroarene and alkene functionalities. The developed synthetic protocol can be used for higher scale reactions as evident by the oxidation of alcohol at 1 g scale in higher yields by a simple filtration process.
- Kumar, Kamlesh,Kumar, Prashant,Joshi, Penny,Rawat, Diwan S
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supporting information
(2020/03/04)
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- Rediscovering aminal chemistry: Copper(ii) catalysed formation under mild conditions
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Aminals, the N,N analogues of acetals, have been thoroughly explored in organic chemistry, with a particular focus on heteroaromatic aldehyde lithiation. Nevertheless, the existing methodologies for their formation typically employ harsh conditions limiting their usefulness. In this work, we present an efficient and mild methodology for the preparation of aminals from aromatic aldehydes, including furanic platforms. These mild conditions allowed ease of access to a plethora of aminals and as such we set out to explore previously unaccessible potential applications. By studying the stability of various aminals, we were able to develop a simple aldehyde protecting group based on a commercial diamine which is deprotected under mind conditions. We developed a protocol for the scavenging of genotoxic aldehydes by taking advantage of our methodology and a diamine resin, as well as early studies on the development of a stimuli-responsive release system using a salycil aldehyde derived aminal. This journal is
- Afonso, Carlos A. M.,António, Jo?o P. M.,Gomes, Rafael F. A.,Mendon?a, Ricardo,Pereira, Juliana G.
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supporting information
p. 7484 - 7490
(2020/11/18)
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- Fine-Bubble-Slug-Flow Hydrogenation of Multiple Bonds and Phenols
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We describe a promising method for the continuous hydrogenation of alkenes or alkynes by using a newly developed fine-bubble generator. The fine-bubble-containing slug-flow system was up to 1.4 times more efficient than a conventional slug-flow method. When applied in the hydrogenation of phenols to the corresponding cyclohexanones, the fine bubble-slug-flow method suppressed over-reduction. As this method does not require the use of excess gas, it is expected to be widely applicable in improving the efficiency of gas-mediated flow reactions.
- Iio, Takuya,Nagai, Kohei,Kozuka, Tomoki,Sammi, Akhtar Mst,Sato, Kohei,Narumi, Tetsuo,Mase, Nobuyuki
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supporting information
p. 1919 - 1924
(2020/11/09)
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- A tunable synthesis of either benzaldehyde or benzoic acid through blue-violet LED irradiation using TBATB
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In this paper, a highly efficient, metal-free, and homogeneous method for the selective aerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visible light was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selective oxidation to aldehyde or carboxylic acid.
- Mardani, Atefeh,Heshami, Marouf,Shariati, Yadollah,Kazemi, Foad,Abdollahi Kakroudi, Mazaher,Kaboudin, Babak
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- Method of preparing L-menthone from R-citronellal
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The invention discloses a method of preparing L-menthone from R-citronellal. Under the action of a Pd-Co-MOF-MMT catalyst, R-citronellal carries out heterogeneous catalytic reactions to generate L-menthone, the conversion rate of R-citronellal can reach 90-99.9%, the yield of L-menthone can reach 85-98%, and the ee value of menthone can reach 95-99.99%.
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Paragraph 0093-0094
(2020/04/06)
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- Method for preparation of L-menthone from R-citronellal
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The invention discloses a method for preparation of L-menthone from R-citronellal. In the presence of a Ru-Cu-MOF catalyst, R-citronellal is cyclized to prepare L-menthone, the reaction conditions aremild, the reaction enantioselectivity is 90%-99.5%, the conversion rate can reach 95%-99.9%, and the ee value of menthone can reach 90%-99.9%.
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Paragraph 0094; 0095
(2020/04/02)
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- A method for the preparation of aldehydes
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The invention discloses a method for the preparation of ketone, relates to the field of organic synthesis. This invention adopts the organic solvent as a medium, cyclopropene [...] derivative as an active agent, activated DMSO oxidation [...] oxidation. The method of the invention is simple, easy to operate, rapid reaction rate, mild reaction, the reaction rate can be adjusted, more economic, to achieve industrial laid the foundation.
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Paragraph 0132; 0133
(2019/05/28)
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- A process for preparing optically pure L - menthones method and used for the method of the catalyst
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The present invention provides a process for preparing optically pure L - menthones method and used for the method of the catalyst. Under the action of the oxidation catalyst, L - menthol to the menthol in the selective oxidation, preparation of the optically pure L - menthones. The oxidation catalyst comprises a chiral salen manganese compound and hydrogen peroxide. The stereoselectivity L - menthones of synthesis, the optical purity of the product can be as high as 99 ee %.
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Paragraph 0057; 0058; 0061-0064
(2019/05/15)
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- Heterogeneously Catalysed Oxidative Dehydrogenation of Menthol in a Fixed-Bed Reactor in the Gas Phase
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For the first time, the oxidative dehydrogenation of (?)-menthol to (?)-menthone and (+)-isomenthone in a marketable quality was carried out in a continuous gas phase reactor as a sustainable process using molecular oxygen as green oxidant and solid catalysts which do not contaminate the product mixture and which are easily to remove. The diastereomeric purity remained largely unchanged. Three types of catalysts were found to be very active and selective in the formation of menthone and isomenthone: AgSr/SiO2, CuO distributed on a basic support and RuMnCe/CeO2, where Ru, Mn and Ce exist in an oxidized state. The best overall yield of menthon/isomenthone obtained with an Ag-based catalyst was 58 % at 64 % selectivity, with a Cu-based catalyst 41 % at 51 % selectivity and with a Ru-based catalyst 68 % at 73 % selectivity. Reaction conditions were widely optimized.
- Kulik, Anna,Neubauer, Katja,Eckelt, Reinhard,Bartling, Stephan,Panten, Johannes,K?ckritz, Angela
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p. 1066 - 1075
(2019/06/24)
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- Chemoselective Hydrogenation of α,β-Unsaturated Carbonyls Catalyzed by Biomass-Derived Cobalt Nanoparticles in Water
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Herein, we report highly chemoselective hydrogenation of α,β-unsaturated carbonyls to saturated carbonyls catalyzed by cobalt nanoparticles supported on the biomass-derived carbon from bamboo shoots with molecular hydrogen in water, which is the first prototype using a heterogeneous non-noble metal catalyst for such organic transformation as far as we know. The optimal cobalt nanocatalyst, CoOx@NC-800, manifested remarkable activity and selectivity for hydrogenation of C=C in α,β-unsaturated carbonyls under mild conditions. A broad set of α,β-aromatic and aliphatic unsaturated carbonyls were selectively reduced to their corresponding saturated carbonyls in up to 99 % yields with good tolerance of various functional groups. Meanwhile, a new straightforward one-pot cascade synthesis of saturated carbonyls was realized with high activity and selectivity via the cross-aldol condensation of ketones with aldehydes followed by selective hydrogenation. More importantly, this one-pot strategy is applicable for the expedient synthesis of Loureirin A, a versatile bioactive and medicinal molecule, from readily available starting materials, further highlighting the practical utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without significant loss in both activity and selectivity.
- Song, Tao,Ma, Zhiming,Yang, Yong
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p. 1313 - 1319
(2019/01/25)
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- Menthane-Based Chloride-Bridged η3-Bis-π-Allylpalladium Chloride Dimers: Catalytic Asymmetric Allylation of Imines
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Menthane-based η3-bis-π-allylpalladium chloride dimer complexes have been prepared for the first time. They exist as dimeric η3-bis-π-allylpalladium with four chloride bridges. The complexes catalyze the asymmetric allylation of vari
- Jha, Amit K.,Fernandes, Rodney A.
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p. 2857 - 2863
(2019/05/15)
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- Chemoselective Oxidation of Equatorial Alcohols with N-Ligated λ3-Iodanes
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The site-selective and chemoselective functionalization of alcohols in complex polyols remains a formidable synthetic challenge. Whereas significant advancements have been made in selective derivatization at the oxygen center, chemoselective oxidation to the corresponding carbonyls is less developed. In cyclic systems, whereas the selective oxidation of axial alcohols is well known, a complementary equatorial selective process has not yet been reported. Herein we report the utility of nitrogen-ligated (bis)cationic λ3-iodanes (N-HVIs) for alcohol oxidation and their unprecedented levels of selectivity for the oxidation of equatorial over axial alcohols. The conditions are mild, and the simple pyridine-ligated reagent (Py-HVI) is readily synthesized from commercial PhI(OAc)2 and can be either isolated or generated in situ. Conformational selectivity is demonstrated in both flexible 1,2-substituted cyclohexanols and rigid polyol scaffolds, providing chemists with a novel tool for chemoselective oxidation.
- Mikhael, Myriam,Adler, Sophia A.,Wengryniuk, Sarah E.
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supporting information
p. 5889 - 5893
(2019/08/26)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- Method for preparing menthone
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The invention discloses a method for preparing menthone. In the method, menthone is synthesized by reaction of isopulegol with a catalytic active component loaded on modified resin as a catalyst. Thecatalytic active component is loaded on the resin by low temperature ultraviolet treatment, and isopulegol is made into menthone by heterogeneous catalysis under mild conditions. The catalytic activecomponent is loaded on the resin; because of the synergistic action of the catalytic active component and the resin, the reaction can be carried out efficiently and rapidly under the mild conditions,the conversion rate of the reaction can reach 90-99.9%, the chemical selectivity can reach 89-99.9%, the catalyst has a long life, the activity of the catalyst is basically stable after the catalyst is reused for 20 times, and the catalyst is reused maximally for 50 times.
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Paragraph 0082; 0084-0087; 0113-0128
(2019/02/13)
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- Chemoselective transfer hydrogenation of Α,Β-unsaturated carbonyls catalyzed by a reusable supported Pd nanoparticles on biomass-derived carbon
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We herein report highly chemoselective transfer hydrogenation of α,β-unsaturated carbonyl compounds to saturated carbonyls with formic acid as a hydrogen donor over a stable and recyclable heterogeneous Pd nanoparticles (NPs) on N,O-dual doped hierarchical porous biomass-derived carbon. The synergistic effect between Pd NPs and incorporated heteroatoms on carbon plays a critical role on promoting the reaction efficiency. A series of α,β-aromatic and aliphatic unsaturated carbonyl compounds was selectively reduced to their corresponding saturated carbonyls in up to 97% isolated yields with good tolerance of various functional groups. In addition, the catalyst can be successively reused for at least 6 times without significant loss in reaction efficiency.
- Song, Tao,Duan, Yanan,Yang, Yong
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- Method for producing Isopulegol from menthone
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Preparing menthone from isopulegol, comprises carrying out dehydrogenation- or hydrogenation reaction in liquid phase using a homogeneously dissolved catalyst comprising at least one metal atom of the group 8, 9 or 10. An independent claim is also included for the reaction product obtainable by the above method.
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Paragraph 0070; 0071; 0072; 0073; 0074; 0075; 0076-0078
(2019/05/16)
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- Method for preparing L-menthone
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The invention provides a method for preparing L-menthone. The method starts from isopulegol containing L-isopulegol, and prepares L-menthone through a method for selectively catalyzing the L-isopulegol to generate hydrogen transfer. The method has advantages of being simple in operation, low in catalyst cost, high in product yield and less in three wastes (waste gas, waste water and industrial residue); through a technology of hydrogenation transfer, the using of hydrogen is not needed, so that the method has better technology safety, and is suitable for industrial production application. TheL-menthone can be performed by performing selective hydrogen transfer on the L-isopulegol in the isopulegol under the action of a transition metal catalyst through the provided method; and the transition metal catalyst includes a transition metal compound and a chiral phosphine ligand.
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Paragraph 0058; 0059; 0064-0066; 0069-0083
(2019/05/08)
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- Desulfurization method of organic compounds containing mercapto or disulfide bond
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The invention relates to a desulfurization method of organic compounds, in particular, organic compounds containing mercapto or a disulfide bond. The method comprises following steps: dissolving organic compounds containing mercapto or a disulfide bond by a solvent; adding a phosphine reagent and an initiator; and carrying out reactions in the presence of light to convert the substrate into corresponding desulfurization products. The organic compounds containing mercapto or a disulfide bond is R-SH or R-S-S-R; wherein R represents a primary carbon group, a secondary carbon group, a tertiary carbon group, an aryl group, or an acyl group. The reactions do not need any metal, and the reaction conditions are mild. Moreover, the desulfurization method has the advantages of high yield, wide substrate application range, and multiple suitable solvents, and is widely suitable for multiple kinds of mercapto-removing reactions and desulfurization reactions of disulfide.
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Paragraph 0026
(2019/10/01)
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- Method for preparing high-purity L-menthone
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The invention discloses a method for preparing high-purity L-menthone. The method includes: under action of a solid base loaded ruthenium catalyst, subjecting raw material L-isopulegol for heterogeneous catalytic reaction to obtain a product-high-purity L-menthone. In mild reaction conditions, the ruthenium catalyst loaded on solid base is utilized to heterogeneously catalyze L-isopulegol to prepare L-menthone with high yield, the catalyst can be recycled conveniently and quickly, and the method is simpler in reaction process, low in reaction cost and high in environment friendliness; througha hydrogenation transfer process, hydrogen is not needed, so that the method has better process safety and industrial prospect.
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Paragraph 0071-0074; 0075-0078; 0079-0082; 0083-0096
(2019/04/06)
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- ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
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The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
- Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
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supporting information
p. 4556 - 4561
(2018/03/13)
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- Nitrosotetrazolium-Catalyzed Aerobic Oxidation of Alcohols to the Corresponding Carbonyl Compounds
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A mesoionic-nitrosotetrazolium-catalyzed aerobic oxidation of alcohols is reported. In the presence of catalytic amounts of 5-nitroso-1,3-diphenyltetrazolium tetrafluoroborate (5 mol-%) and nitric acid (20 mol-%), a wide range of alcohols are oxidized to the corresponding aldehydes and ketones in yields of 53–100 % at room temperature under ambient air or oxygen conditions. This oxidation shows a strong preference for secondary alcohols over primary alcohols; sterically hindered alcohols are also smoothly oxidized. A mechanism involving a nitroso/NOx catalytic cycle is proposed.
- Matsukawa, Yuta,Hirashita, Tsunehisa,Araki, Shuki
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p. 1359 - 1363
(2018/04/02)
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- Chemoenzymatic Synthesis of the Intermediates in the Peppermint Monoterpenoid Biosynthetic Pathway
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A chemoenzymatic approach providing access to all four intermediates in the peppermint biosynthetic pathway between limonene and menthone/isomenthone, including noncommercially available intermediates (-)-trans-isopiperitenol (2), (-)-isopiperitenone (3), and (+)-cis-isopulegone (4), is described. Oxidation of (+)-isopulegol (13) followed by enolate selenation and oxidative elimination steps provides (-)-isopiperitenone (3). A chemical reduction and separation route from (3) provides both native (-)-trans-isopiperitenol (2) and isomer (-)-cis-isopiperitenol (18), while enzymatic conjugate reduction of (-)-isopiperitenone (3) with IPR [(-)-isopiperitenone reductase)] provides (+)-cis-isopulegone (4). This undergoes facile base-mediated chemical epimerization to (+)-pulegone (5), which is subsequently shown to be a substrate for NtDBR (Nicotiana tabacum double-bond reductase) to afford (-)-menthone (7) and (+)-isomenthone (8).
- Cheallaigh, Aisling Ní,Mansell, David J.,Toogood, Helen S.,Tait, Shirley,Lygidakis, Antonios,Scrutton, Nigel S.,Gardiner, John M.
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p. 1546 - 1552
(2018/08/04)
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- Solventless, selective and catalytic oxidation of primary, secondary and benzylic alcohols by a Merrifield resin supported molybdenum(vi) complex with H2O2 as an oxidant
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Here, we have described the synthesis, characterization and catalytic activity of a dioxo-molybdenum(vi) complex supported on functionalized Merrifield resin (MR-SB-Mo). The functionalization of Merrifield resin (MR) was achieved in two-steps viz. carbonylation (MR-C) and Schiff base formation (MR-SB). The compounds, MR-C, MR-SB and MR-SB-Mo, were characterized at each step of the synthesis by elemental, SEM, EDX, thermal, BET and different spectroscopic analysis. The catalyst, MR-SB-Mo, efficiently and selectively oxidized a wide variety of alcohols to aldehydes or ketones using 30% H2O2 as an oxidant with reasonably good TOF (660 h-1 in case of benzyl alcohol). The catalyst acted heterogeneously under solventless reaction conditions and did not lead to over oxidized products under optimized conditions. The catalyst afforded regeneration and can be reused for at least five reaction cycles without loss of efficiency and product selectivity. A reaction mechanism for the catalytic activity of MR-SB-Mo was proposed and a probable reactive intermediate species isolated.
- Boruah, Jeena Jyoti,Das, Siva Prasad
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p. 34491 - 34504
(2018/10/21)
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- Iron(III) Complexes with Cross-Bridged Cyclams: Synthesis and Use in Alcohol and Water Oxidation Catalysis
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A class of iron(III) complexes containing diversely substituted cross-bridged cyclams (1-R,R′: 1-Me,Me, 1-Me,Et, 1-Et,Et, 1-Me,Bn, 1-Bn,Bn) has been prepared and characterized. (1-R,R′) complexes catalyze the oxidation of alcohols to ketones in green cond
- Annunziata, Alfonso,Esposito, Roberto,Gatto, Giordano,Cucciolito, Maria Elena,Tuzi, Angela,Macchioni, Alceo,Ruffo, Francesco
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p. 3304 - 3311
(2018/07/31)
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- HYDROSILANE/LEWIS ACID ADDUCT, PARTICULARLY ALUMINUM, IRON, AND ZINC, METHOD FOR PREPARING SAME, AND USE OF SAID SAME IN REACTIONS FOR REDUCING CARBONYL DERIVATIVES
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Disclosed is an adduct between a Lewis acid, preferably aluminum trichloride, iron trichloride, or zinc dichloride, and a hydrosilane;—a method for preparing same; and a method for for reducing, particularly, an aldehyde, a ketone, an α,β-unsaturated ketone, an imine, or an α,β-unsaturated imine.
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Paragraph 0210; 0211; 0212
(2018/02/28)
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- Arylruthenium(III) Porphyrin-Catalyzed C-H Oxidation and Epoxidation at Room Temperature and [RuV(Por)(O)(Ph)] Intermediate by Spectroscopic Analysis and Density Functional Theory Calculations
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The development of highly active and selective metal catalysts for efficient oxidation of hydrocarbons and identification of the reactive intermediates in the oxidation catalysis are long-standing challenges. In the rapid hydrocarbon oxidation catalyzed by ruthenium(IV) and -(III) porphyrins, the putative Ru(V)-oxo intermediates remain elusive. Herein we report that arylruthenium(III) porphyrins are highly active catalysts for hydrocarbon oxidation. Using catalyst [RuIII(TDCPP)(Ph)(OEt2)] (H2TDCPP = 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin), the oxidation of C-H bonds of various hydrocarbons with oxidant m-CPBA at room temperature gave alcohols/ketones in up to 99% yield within 1 h; use of [nBu4N]IO4 as a mild alternative oxidant avoided formation of lactone from cyclic ketone in C-H oxidation, and the catalytic epoxidation with up to 99% yield and high selectivity (no aldehydes as side product) was accomplished within 5 min. UV-vis, electrospray ionization-mass spectrometry, resonance Raman, electron paramagnetic resonance, and kinetic measurements and density functional theory calculations lend evidence for the formation of Ru(V)-oxo intermediate [RuV(TDCPP)(O)(Ph)].
- Shing, Ka-Pan,Cao, Bei,Liu, Yungen,Lee, Hung Kay,Li, Ming-De,Phillips, David Lee,Chang, Xiao-Yong,Che, Chi-Ming
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supporting information
p. 7032 - 7042
(2018/06/12)
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- Revisiting Sodium Hypochlorite Pentahydrate (NaOCl·5H 2 O) for the Oxidation of Alcohols in Acetonitrile without Nitroxyl Radicals
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Sodium hypochlorite pentahydrate (NaOCl·5H 2 O) is capable of oxidizing alcohols in acetonitrile at 20 °C without the use of catalysts. The oxidation is selective to allylic, benzylic, and secondary alcohols. Aliphatic primary alcohols are not oxidized.
- Hirashita, Tsunehisa,Sugihara, Yuto,Ishikawa, Shota,Naito, Yohei,Matsukawa, Yuta,Araki, Shuki
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p. 2404 - 2407
(2018/11/23)
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- Synthesis of an oligomer ruthenium complex and its catalysis in the oxidation of alcohols
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A ligand with both a terpyridine and a pyridine-2,6-dicarboxylate group (abbreviated as terpy-pydic) was designed and synthesized. This ligand reacted with [Ru(p-cymene)Cl2]2 to afford a novel oligomer ruthenium complex named as oligomer-Ru(terpy)(pydic) which was characterized thoroughly. Under the catalysis of this oligomer ruthenium complex, different sorts of secondary alcohols were oxidized to the corresponding kenones by the oxidant tert-butyl hydroperoxide. Besides, this catalyst can be readily recovered and recycled several times without a large loss of its efficiency.
- Zhang, Yuecheng,Huo, Wenge,Zhang, Hong-Yu,Zhao, Jiquan
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p. 47261 - 47270
(2017/10/19)
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- Ruthenium-phenol catalysts and method of preparing menthone from isopulegol
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The present invention is directed towards a catalyst which is obtainable by contacting in situ a ruthenium precursor and a phenol derivative. Furthermore, the present invention is directed towards the use of said catalyst in transfer hydrogenation reactions. In particular, the present invention is directed to a method for preparing menthone starting from isopulegol.
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Page/Page column 25
(2017/11/09)
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- Heterogeneous Ru(iii) oxidation catalysts: Via 'click' bidentate ligands on a periodic mesoporous organosilica support
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A 100% monoallyl ring-type Periodic Mesoporous Organosilica (PMO) is prepared as a novel, versatile and exceptionally stable catalytic support with a high internal surface area and 5.0 nm pores. Thiol-ene 'click' chemistry allows straightforward attachment of bifunctional thiols (-NH2, -OH, -SH) which, exploiting the thioether functionality formed, give rise to 'solid' bidentate ligands. [Ru(acac)2(CH3CN)2]PF6 is attached and complex formation on the solid is studied via density functional theory. All resulting solid catalysts show high activity and selectivity in alcohol oxidation reactions performed in green conditions (25 °C/water). The PMO catalysts do not leach Ru during reaction and are thus easily recuperated and re-used for several runs. Furthermore, oxidation of poorly water-soluble (±)-menthol illustrates the benefits of using hydrophobic PMOs as catalytic supports.
- Clerick, Sander,De Canck, Els,Hendrickx, Kevin,Van Speybroeck, Veronique,Van Der Voort, Pascal
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p. 6035 - 6045
(2018/06/06)
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- An alkoxyamine compound, alkoxy alcohol oxidation catalyst and method of using the alcohol oxidation
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PROBLEM TO BE SOLVED: To provide a novel alkoxyamine compound which can be easily manufactured and applied suitably as an alcohol oxidation catalyst capable of exerting sufficiently high catalytic activity in oxidation of primary and secondary alcohols.SOLUTION: There is provided an alkoxyamine compound with a homoadamantane skeleton represented by the general formula (1) in the figure. [In the formula (1), Rand Rare each independently any one selected from the group consisting of a hydrogen atom and alkyl groups that may be substituted.
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Paragraph 0096; 0098-0100
(2017/02/02)
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- Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals; An effective re-oxidant for TEMPO oxidation
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The novel oxidant of sodium hypochlorite pentahydrate (NaOCl·5H2O), which is now available for industrial and laboratory use has several advantageous properties. The crystalline material has 44% of NaOCl, contains minimal sodium hydroxide and sodium chloride, and the aqueous solution indicates pH 11-12. Herein, NaOCl·5H2O crystals are examined for use as an oxidant for primary and secondary alcohols, with or without nitroxyl radicals, in the presence or absence of phase-transfer catalysts. The pentahydrate crystals alone (without nitroxyl radicals) demonstrate a powerful oxidizing ability, converting secondary alcohols to the corresponding ketones. In the presence of TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) or 1-Me-AZADO (1-methyl-2-azaadamantane N-oxy radical), sterically hindered secondary alcohols are oxidized without pH adjustment. A proposed mechanism for the oxidation is discussed.
- Okada, Tomohide,Asawa, Tomotake,Sugiyama, Yukihiro,Iwai, Toshiaki,Kirihara, Masayuki,Kimura, Yoshikazu
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p. 2818 - 2827
(2016/05/19)
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- Nanopalladium-catalyzed conjugate reduction of Michael acceptors-application in flow
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A continuous-flow approach towards the selective nanopalladium-catalyzed hydrogenation of the olefinic bond in various Michael acceptors, which could lead to a greener and more sustainable process, has been developed. The nanopalladium is supported on aminofunctionalized mesocellular foam. Both aromatic and aliphatic substrates, covering a variation of functional groups such as acids, aldehydes, esters, ketones, and nitriles were selectively hydrogenated in high to excellent yields using two different flow-devices (H-Cube and Vapourtec). The catalyst was able to hydrogenate cinnamaldehyde continuously for 24 h (in total hydrogenating 19 g cinnanmaldehyde using 70 mg of catalyst in the H-cube) without showing any significant decrease in activity or selectivity. Furthermore, the metal leaching of the catalyst was found to be very low (ppb amounts) in the two flow devices.
- Nagendiran, Anuja,S?rensen, Henrik,Johansson, Magnus J.,Tai, Cheuk-Wai,B?ckvall, Jan-E.
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supporting information
p. 2632 - 2637
(2016/05/24)
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- Selective aqueous oxidation of alcohols catalyzed by copper (II) phthalocyanine nanoparticles
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A new catalyst based on metallophthalocyanine nanoparticles has been synthesized and characterized by scanning electron microscopy (SEM). The aqueous oxidation of alcohols to the corresponding carbonyl compounds (aldehydes and ketones) has been studied us
- Kheirjou, Somayyeh,Kheirjou, Ramin,Rezayan, Ali Hossein,Shakourian-Fard, Mehdi,Mahmoudi Hashemi, Mohammad
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p. 313 - 318
(2016/04/20)
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- Two New 1,1,3,3-Tetramethylguanidinium Halochromates (C5H14N3CrO3X) (X: Cl, F): Efficient Reagents for Oxidation of Organic Substrates under Solvent-Free Conditions and Microwave Irradiation
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Two new mild oxidizing agents 1,1,3,3-tetramethylguanidinium fluorochromate (TMGFC) and 1,1,3,3-tetramethylguanidinium chlorochromate (TMGCC) were prepared in high yields by reacting tetramethylguanidine with CrO3 and related acid. These reagents are suitable to oxidize various primary and secondary alcohols and oximes to the corresponding carbonyl compounds under solvent-free conditions and microwave irradiation.
- ?endil, Kivilcim,?zgün, H. Beytiye,üstün, Ebru
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- Simple and Efficient Ruthenium-Catalyzed Oxidation of Primary Alcohols with Molecular Oxygen
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Oxidative transformations utilizing molecular oxygen (O2) as the stoichiometric oxidant are of paramount importance in organic synthesis from ecological and economical perspectives. Alcohol oxidation reactions that employ O2are scarce in homogeneous catalysis and the efficacy of such systems has been constrained by limited substrate scope (most involve secondary alcohol oxidation) or practical factors, such as the need for an excess of base or an additive. Catalytic systems employing O2as the “primary” oxidant, in the absence of any additive, are rare. A solution to this longstanding issue is offered by the development of an efficient ruthenium-catalyzed oxidation protocol, which enables smooth oxidation of a wide variety of primary, as well as secondary benzylic, allylic, heterocyclic, and aliphatic, alcohols with molecular oxygen as the primary oxidant and without any base or hydrogen- or electron-transfer agents. Most importantly, a high degree of selectivity during alcohol oxidation has been predicted for complex settings. Preliminary mechanistic studies including18O labeling established the in situ formation of an oxo–ruthenium intermediate as the active catalytic species in the cycle and involvement of a two-electron hydride transfer in the rate-limiting step.
- Ray, Ritwika,Chandra, Shubhadeep,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 8814 - 8822
(2016/07/06)
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