- Tetrabutylammonium peroxydisulfate in organic synthesis; II. A mild method for cleaving tosylhydrazones with tetrabutylammonium peroxydisulfate
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Tosylhydrazones are oxidized with tetrabutylammonium peroxydisulfate in 1,2-dichloroethane to afford the corresponding ketones in excellent yields under neutral conditions.
- Chen,Yang,Zhang,Guan,Wan
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- Mild Chemoenzymatic Oxidation of Allylic sec-Alcohols. Application to Biocatalytic Stereoselective Redox Isomerizations
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The design of catalytic oxidative methodologies in aqueous medium under mild reaction conditions and using molecular oxygen as final electron acceptor represents a suitable alternative to the traditional oxidative transformations. These methods are especially relevant if other functionalities that can be oxidized are present within the same molecule, as in the case of allylic alcohols. Herein we apply a simple chemoenzymatic system composed of the laccase from Trametes versicolor and 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO) to oxidize a series of racemic allylic sec-alcohols into the corresponding α,β-unsaturated ketones. Afterward, these compounds react with different commercially available ene-reductases to afford the corresponding saturated ketones. Remarkably, in the case of trisubstituted alkenes, the bioreduction reaction occurred with high stereoselectivity. Overall, a bienzymatic one-pot two-step sequential strategy has been described with respect to the synthesis of saturated ketones starting from racemic allylic alcohols, thus resembling the metal-catalyzed redox isomerizations of these derivatives that have been previously reported in the literature.
- Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
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p. 2413 - 2419
(2018/03/13)
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- Highly practical and efficient preparation of aldehydes and ketones from aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst
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Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations.
- Zhang, Mengqi,Zhai, Yongyan,Ru, Shi,Zang, Dejin,Han, Sheng,Yu, Han,Wei, Yongge
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supporting information
p. 10164 - 10167
(2018/09/13)
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- Cooperative Electrocatalytic and Chemoselective Alcohol Oxidation by Shvo's Catalyst
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A new electrocatalytic conversion of alcohols to ketones and aldehydes was developed based on an electrochemical study of Shvo's complex. The oxidation of secondary alcohols was efficiently performed under mild conditions using a catalytic amount of Shvo's catalyst, in combination with a sub-stoichiometric amount of 2,6-dimethoxy-1,4-benzoquinone in N,N-dimethylformamide at 80 °C. The hydroquinone thus formed is continuously reoxidized with the aid of an electrochemical device. Excellent yields for different ketones, aromatic as well as aliphatic and α,β-unsaturated ketones, are obtained. In addition, chemoselectivity towards oxidation of the secondary alcohol is achieved when converting vicinal diols such as 1,2-octanediol and 1,2-decanediol. (Figure presented.).
- Lybaert, Jeroen,Trashin, Stanislav,Maes, Bert U. W.,De Wael, Karolien,Abbaspour Tehrani, Kourosch
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supporting information
p. 919 - 925
(2017/03/27)
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- Characterization of the monolignol oxidoreductase AtBBE-like protein 15 L182V for biocatalytic applications
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Monolignol oxidoreductases from the berberine bridge enzyme-like (BBE-like) protein family (pfam 08031) catalyze the oxidation of monolignols to the corresponding aldehydes. In this report, we explore the potential of a monolignol oxidoreductase from Arabidopsis thaliana (AtBBE-like protein 15) as biocatalyst for oxidative reactions. For this study we employed a variant with enhanced reactivity towards oxygen, which was obtained by a single amino acid exchange (L182V). The pH and temperature optima of the purified AtBBE-like protein 15 L182V were determined as well as the tolerance toward organic co-solvents; furthermore the substrate scope was characterized. The enzyme has a temperature optimum of 50 °C and retains more than 50% activity between pH 5 and pH 10 within 5 min. The enzyme shows increased activity in the presence of various co-solvents (10–50% v/v), including acetonitrile, 2-propanol, 1,4-dioxane, and dimethyl sulfoxide. Primary benzylic and primary or secondary allylic alcohols were accepted as substrates. The enantioselectivity E in the oxidation of secondary alcohols was good to excellent (E>34 to?>200).
- Pils, Sabine,Schnabl, Kordula,Wallner, Silvia,Daniel, Bastian,Macheroux, Peter,Kljajic, Marko,Kupresanin, Nina,Breinbauer, Rolf,Fuchs, Michael,Rocha, Raquel,Schrittwieser, Joerg H.,Kroutil, Wolfgang
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- Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid
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The tungsten oxide/2,2′-bipyridine hybrid material [WO3(2,2′-bpy)]·nH2O (n = 1-2) (1) has been prepared in near quantitative yield by the reaction of H2WO4, 2,2′-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160°C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞1[WO3(2,2′-bpy)], topologically identical to that found in the previously reported anhydrous phases [MO3(2,2′-bpy)] (M = Mo, W). While in the latter the N,N′-chelated 2,2′-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2′-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based (pre)catalysts, including the hybrid polymer [MoO3(2,2′-bpy)]. While the latter exhibits superior performance when tert-butyl hydroperoxide (TBHP) is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3(2,2′-bpy)] act as sources of soluble active species, namely, the oxodiperoxo complex [MO(O2)2(2,2′-bpy)], which is formed in situ. Compounds 1 and [WO(O2)2(2,2′-bpy)] (2) were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, (R)-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.
- Amarante, Tatiana R.,Antunes, Margarida M.,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
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p. 9690 - 9703
(2015/11/03)
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- Wacker-type oxidation and dehydrogenation of terminal olefins using molecular oxygen as the sole oxidant without adding ligand
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An efficient and economical palladium-catalyzed oxidation system has been identified. The oxidation system, characterized by not adding ligand and using molecular oxygen as the sole oxidant, can realize the Tsuji-Wacker oxidation of terminal olefins and especially styrenes to methyl ketones; in addition, this system can achieve tandem Wacker oxidation-dehydrogenation of terminal olefins to α,β-unsaturated ketones.
- Wang, Yu-Fei,Gao, Ya-Ru,Mao, Shuai,Zhang, Yan-Lei,Guo, Dong-Dong,Yan, Zhao-Lei,Guo, Shi-Huan,Wang, Yong-Qiang
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supporting information
p. 1610 - 1613
(2014/04/17)
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- Chemoselective hydrogen peroxide oxidation of allylic and benzylic alcohols under mild reaction conditions catalyzed by simple iron-picolinate complexes
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Chemoselective oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds proceeded efficiently using hydrogen peroxide with iron-picolinate catalysts. The in situ generated [Fe(Me-Pic)3] (Me-Pic = 6-methylpicolinate) catalyzed oxidation of the alcohol moiety of primary allylic alcohols while the [Fe(Pic)3] (Pic = picolinate) and [Fe(Me-Pic)2(Pic)] did not show sufficient catalytic activity. the Partner Organisations 2014.
- Tanaka, Shinji,Kon, Yoshihiro,Nakashima, Takuya,Sato, Kazuhiko
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p. 37674 - 37678
(2014/11/07)
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- Chemoselective hydrogen peroxide oxidation of allylic and benzylic alcohols under mild reaction conditions catalyzed by simple iron-picolinate complexes
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Chemoselective oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds proceeded efficiently using hydrogen peroxide with iron-picolinate catalysts. The in situ generated [Fe(Me-Pic)3] (Me-Pic = 6-methylpicolinate) catalyzed oxidation of the alcohol moiety of primary allylic alcohols while the [Fe(Pic)3] (Pic = picolinate) and [Fe(Me-Pic)2(Pic)] did not show sufficient catalytic activity. This journal is
- Tanaka, Shinji,Kon, Yoshihiro,Nakashima, Takuya,Sato, Kazuhiko
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p. 37674 - 37678
(2014/12/11)
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- COMPOUNDS AND METHODS FOR ALTERING LIFESPAN OF EUKARYOTIC ORGANISMS
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Provided are compounds which generally have a triketone structure. Examples of the compounds include derivatives of 1,3-cyclohexanedione, such as: 1,3-cyclohexanedione, 2-propanoyl-5-cyclohexyl-; 1,3-cyclohexanedione, 2-propanoyl-5-[4-fluorophenyl]-; 1,3-cyclohexanedione, 2-acetyl-5-[thien-2-yl]-; 1,3-cyclohexanedione, 2-acetyl-5 -butyl-; and 1,3-cyclohexanedione, 2-propanoyl-5-[bicyclo[2.2.1]hept-2-en-5-yl]-. The compounds can be used to alter the lifespan of eukaryotic organisms and treat inflammation.
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Page/Page column 20
(2011/06/19)
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- Gold nanoparticle-catalyzed environmentally benign deoxygenation of epoxides to alkenes
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We have developed a highly efficient and green catalytic deoxygenation of epoxides to alkenes using gold nanoparticles (NPs) supported on hydrotalcite [HT: Mg6Al2CO3(OH)16] (Au/HT) with alcohols, CO/H2O or H2 as the reducing reagent. Various epoxides were selectively converted to the corresponding alkenes. Among the novel metal NPs on HT, Au/HT was found to exhibit outstanding catalytic activity for the deoxygenation reaction. Moreover, Au/HT can be separated from the reaction mixture and reused with retention of its catalytic activity and selectivity. The high catalytic performance of Au/HT was attributed to the selective formation of Au-hydride species by the cooperative effect between Au NPs and HT.
- Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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scheme or table
p. 8209 - 8227
(2011/12/14)
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- Supported gold and silver nanoparticles for catalytic deoxygenation of epoxides into alkenes
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Taking the 'O': Supported gold and silver nanoparticles (NPs), which are wellknown epoxidation catalysts, were found to have intrinsic catalytic ability for the deoxygenation of epoxides into alkenes using alcohol as a reductant (see picture). The selectivity for all the alkenes were over 99%, and an excellent turnover number was achieved. Furthermore, these supported gold and silver nanoparticles were recyclable. Figure Presented
- Mitsudome, Takato,Noujima, Akifumi,Mikami, Yusuke,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; scheme or table
p. 5545 - 5548
(2010/09/05)
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- Efficient aerobic oxidation of alcohols using a hydrotalcitesupported gold nanoparticle catalyst
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Hydrotalcite-supported gold nanoparticles (Au/HT) were found to be a highly efficient heterogeneous catalyst for the aerobic oxidation of alcohols under mild reaction conditions (4O°C, in air). This catalyst system does not require any additives and is applicable to a wide range of alcohols, including less reactive cyclohexanol derivatives. This Au/HT catalyst could also function in the oxidation of 1-phenylethanol under neat conditions; the turnover number (TON) and turnover frequency (TOF) reached 200,000 and 8,300 h -1, respectively. These values are among the highest values compared to those of other reported catalyst systems at high conversion. Moreover, the Au/HT can be recovered by simple filtration and reused without any loss of its activity and selectivity.
- Mitsudome, Takato,Noujima, Akifumi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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scheme or table
p. 1890 - 1896
(2011/03/18)
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- Catalyst parameters determining activity and selectivity of supported gold nanoparticles for the aerobic oxidation of alcohols: The molecular reaction mechanism
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As previously reported for for solventless reactions, gold nanoparticles supported on ceria are also excellent general heterogeneous catalysts for the aerobic oxidations of alcohols in organic solvents. Among organic solvents it was found that toluene is a convenient one. A systematic study on the influence of the particle size and gold content on the support has established that the activity correlates linearly with the total number of external gold atoms, and with the surface coverage of the support. Amongst catalysts with different supports, but similar gold particle size and content, gold on ceria exhibits the highest activity. By means of a kinetic study (influence of σ+ parameter, kinetic isotopic effect, temperature, alcohol concentration and oxygen pressure) a mechanistic proposal consisting of the formation of metalalcoholate, β-hydride shift from carbon to metal and M-H oxidation has been proposed that explains all experimental results.
- Abad, Alberto,Corma, Avelino,Garcia, Hermenegildo
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p. 212 - 222
(2008/09/18)
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- Unique gold chemoselectivity for the aerobic oxidation of allylic alcohols
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Gold nanoparticles supported on nanocrystalline ceria has been found to be more active and chemoselective than palladium and gold(core)-palladium(shell) nanoparticles for the aerobic oxidation of allylic alcohols. The Royal Society of Chemistry 2006.
- Abad, Alberto,Almela, Carles,Corma, Avelino,Garcia, Hermenegildo
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p. 3178 - 3180
(2008/09/19)
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- Controlled synthesis of hydroxyapatite-supported palladium complexes as highly efficient heterogeneous catalysts
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Achieving precise control of active species on solid surfaces is one of the most important goals in the development of highly functionalized heterogeneous catalysts. The treatment of hydroxyapatites with PdCl2(PhCN)2 gives two new types of hydroxyapatite-bound Pd complexes. Using the stoichiometric hydroxyapatite, Ca10(PO4)6(OH)2, we found that monomeric PdCl2 species can be grafted on its surface, which are easily transformed into Pd0 particles with narrow size distribution in the presence of alcohols. Such metallic Pd species can effectively promote alcohol oxidation using molecular oxygen and are shown to give a remarkably high TON of up to 236000. Another monomeric PdII phosphate complex can be generated at a Ca-deficient site of the nonstoichiometric hydroxyapatite, Ca9(HPO4)(PO4)5(OH), affording a catalyst with PdII structure and high activity for the Heck and Suzuki reactions. To the best of our knowledge, the PdHAP are one of the most active heterogeneous catalysts for both alcohol oxidation under an atmospheric O2 pressure and the Heck reaction reported to date. These Pd catalysts are recyclable in the above organic reactions. Our approach to catalyst preparation based on the control of Ca/P ratios of hydroxyapatites represents a particularly attractive method for the nanoscale design of catalysts. Copyright
- Mori, Kohsuke,Yamaguchi, Kazuya,Hara, Takayoshi,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 11572 - 11573
(2007/10/03)
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- Diamine-protonic acid catalysts for catalytic asymmetric aldol reaction
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Four different protonic acids and 15 diamines were screened in the catalytic asymmetric direct aldol reaction of three different aldehydes in acetone.
- Saito,Nakadai,Yamamoto
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p. 1245 - 1248
(2007/10/03)
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- Use of a Sacrificial Aluminum Anode in the Acylation of Some Olefins
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The acylation of some alicyclic and aliphatic alkenes by the electrochemical generation of a catalyst using a sacrificial aluminum anode was investigated. Substrates were electrolyzed in a dichloromethane solution of an appropriate electrolyte (tetraalkylammonium salts) in the presence of an acylating agent (acetyl chloride or anhydride). Thus, unsubstituted cycloalkenes, namely cyclohexene and cycloheptene, gave by that reaction conjugated ketones, i.e. the corresponding 1-acetylcycloalkenes, as the only unsaturated carbonyl compounds in moderate-to-good yields. Under the same reaction conditions their 1-methyl derivatives gave mixtures of the corresponding conjugated and β,γ-unsaturated isomeric ketones in which unconjugated compounds predominate. In both cases unsaturated ketones were accompanied by different amounts of side products. Terminal aliphatic alkenes (1-hexene, 1-heptene, and 1-dodecene) afforded only conjugated a ketone with a normal skeleton, but in lower yields. The acylation of cyclohexene was studied in more detail, altering the reaction conditions by changing the reaction temperature, the supporting electrolyte, the acylating agent and the electrochemical cell. Mechanistic considerations were made on the basis of the products distribution and some theoretical calculations being made by the MOPAC program package (version 7.0).
- Vukicevic, Rastko D.,Joksovic, Ljubinka,Konstantinovic, Stanimir,Markovic, Zoran,Mihailovic, Mihailo Lj.
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p. 899 - 904
(2007/10/03)
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- INDUCTION PAR LA LUMIERE DE L'OXYDATION DES COMPLEXES Η3-ALLYLPALLADIUM PAR L'OXYGENE MOLECULAIRE
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Irradiation at λ=366 nm of oxygenated solutions of η3-allylpalladium complexes leads to unsaturated carbonyl compounds.Substitution of the η3-allyl ligand by an electron withdrawing group could induce a regioselective oxidation of the allylic position farthest from this group.The efficiency of these reactions is sensible to the nature of the solvent.
- Muzart, J.,Pale, P.,Pete, J.P.,Riahi, A.
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p. 731 - 739
(2007/10/02)
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- FORMATION DE CETONES ETHYLENIQUES PAR ACTION D'ACIDE ACETYLSULFOACETIQUE SUR DES ALCENES
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Monoalkyl- and 1,2-dialkylethylenes have a similar behaviour under the action of acetylsulfoacetic acid : the reaction does not necessarily stop after the formation of α- or β-enones, the yield of which is highly influenced by reaction time; thus, 1-acetoxy-1,3-dienes are identified in the case of α-enones.A different behaviour is shown by 1,1-dialkyl and trialkylethylenes, which can constitute an interesting source of highly branched enones.With this second group of alkenes, isomerisation of the alkene is sometimes observed prior to acetylation.Lastly, some alkenes undergo acetoxylation at the same time as acetylation.
- Loiseau, Andre-Michel,Luft, Robert,Zunino, Serge
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p. 144 - 152
(2007/10/02)
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