- Tuning nano-nickel selectivity with tin in flow hydrogenation of 6-methyl-5-hepten-2-one by surface organometallic chemistry modification
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Chemoselective flow hydrogenation of 6-methyl-5-hepten-2-one was performed over nano-nickel catalysts. The parent catalyst composed solely of nickel nanoparticles grafted on the polymeric resin exhibited high activity and selectivity towards C[dbnd]C bond saturation but its modification with small quantities of tin significantly increased its ability to perform C[dbnd]O bond hydrogenation. The post-synthetic modification of the parent catalyst was achieved by surface organometallic chemistry approach and performed in the same flow micro-reactor, which was used for the catalytic studies, providing a methodology for online modification of parent catalysts.
- Zienkiewicz-Machnik, Ma?gorzata,Goszewska, Ilona,?r?bowata, Anna,Kubas, Adam,Giziński, Damian,S?owik, Grzegorz,Matus, Krzysztof,Lisovytskiy, Dmytro,Pisarek, Marcin,Sá, Jacinto
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Read Online
- Study on the selective hydrogenation of isophorone
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3,3,5-Trimethylcyclohexanone (TMCH) is an important pharmaceutical intermediate and organic solvent, which has important industrial significance. The selective hydrogenation of isophorone was studied over noble metal (Pd/C, Pt/C, Ir/C, Ru/C, Pd/SiO2, Pt/SiO2, Ir/SiO2, Ru/SiO2), and non-noble metal (RANEY Ni, RANEY Co, RANEY Cu, RANEY Fe, Ni/SiO2, Co/SiO2, Cu/SiO2, Fe/SiO2) catalysts and using solvent-free and solvent based synthesis. The results show that the solvent has an important effect on the selectivity of TMCH. The selective hydrogenation of isophorone to TMCH can be influenced by the tetrahydrofuran solvent. The conversion of isophorone is 100%, and the yield of 3,3,5-trimethylcyclohexanone is 98.1% under RANEY Ni and THF. The method was applied to the selective hydrogenation of isopropylidene acetone, benzylidene acetone and 6-methyl-5-ene-2-heptanone. The structures of the hydrogenation product target (4-methylpentan-2-one, 4-benzylbutan-2-one and 6-methyl-heptane-2-one) were characterized using 1H-NMR and 13C-NMR. The yields of 4-methylpentan-2-one, 4-benzylbutan-2-one and 6-methyl-heptane-2-one were 97.2%, 98.5% and 98.2%, respectively. The production cost can be reduced by using RANEY metal instead of noble metal palladium. This method has good application prospects. This journal is
- Xu, Lei,Sun, Shaoyin,Zhang, Xing,Gao, Haofei,Wang, Wei
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p. 4465 - 4471
(2021/02/03)
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- Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
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The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
- Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
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supporting information
p. 2157 - 2161
(2021/05/21)
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- Base-free transfer hydrogenation of aryl-ketones, alkyl-ketones and alkenones catalyzed by an IrIIICp* complex bearing a triazenide ligand functionalized with pyrazole
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An IrIIICp* complex (2) bearing a triazenide ligand functionalized with pyrazole was synthesized and fully characterized by spectroscopic methods and the structure confirmed by X-ray diffraction studies. The catalytic activity of 2 and the control complex 3, which lacks of pyrazole in its structure, was evaluated in the reduction of aryl-ketones, alkyl-ketones, α,β-unsaturated and γ,δ-unsaturated ketones. The catalytic system, using either 2 or 3, exhibited good to excellent selectivity when tested with ketones and alkenones at 90 °C in 2-propanol as hydrogen source under base-free conditions. Reactivity of 2 in 2-propanol and NaH gave a neutral metal hydride (4) while in the absence of base gave two major cationic hydrides species (5 and 6).
- Medrano-Castillo, Layla J.,Collazo-Flores, Miguel á.,Camarena-Díaz, Juan P.,Correa-Ayala, Erick,Chávez, Daniel,Grotjahn, Douglas B.,Rheingold, Arnold L.,Miranda-Soto, Valentín,Parra-Hake, Miguel
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- Tuning Nano-Nickel Catalyst Hydrogenation Aptitude by On-the-Fly Zirconium Doping
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The effect of nano-Ni catalyst post-synthetic Zr-modification on hydrogenation reaction of 6-methyl-5-hepten-2-one was investigated in a fixed bed continuous-flow micro-reactor to produce fine chemicals. The catalytic performance revealed that Zr-doping achieved by surface organometallic chemistry approach modifies the natural aptitude of nickel to hydrogenate C=C bond, since the addition of small quantities of zirconium significantly increased the amount of unsaturated and saturated alcohols formed in 6-methyl-5-hepten-2-one hydrogenation. Quantum chemical calculations revealed a stronger interaction between Zr←O=C that promotes the formation of C=C semihydrogenation product and enhances the probability of complete hydrogenation. The on-the-fly strategy presented herein enables for rapid optimization and understanding of catalytic processes.
- Zienkiewicz-Machnik, Ma?gorzata,Goszewska, Ilona,Giziński, Damian,?r?bowata, Anna,Kuzmowicz, Katarzyna,Kubas, Adam,Matus, Krzysztof,Lisovytskiy, Dmytro,Pisarek, Marcin,Jacinto
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p. 3132 - 3138
(2020/05/06)
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- Method for selectively hydrogenating alpha, beta-unsaturated carbonyl compound by cobalt complex
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The invention provides a method for selectively hydrogenating an alpha, beta-unsaturated carbonyl compound. The method for selectively hydrogenating the alpha, beta-unsaturated carbonyl compound comprises the steps that first, a cobalt metal precursor and a carbene ligand are coordinated in a solution to obtain a cobalt complex, and the cobalt complex selectively enables the alpha, beta-unsaturated carbonyl compound to be reduced into a corresponding saturated carbonyl compound in a hydrogen atmosphere under the activation of an activator. The method for selectively hydrogenating the alpha, beta-unsaturated carbonyl compound has the main advantages that cobalt is used as a catalyst, and metal cobalt is cheap and easy to obtain relative to noble metal such as palladium, ruthenium, osmium, iridium and platinum, and the catalyst cost is greatly reduced; secondly, the carbene ligand used in the method has the advantages of simple structure, low price, strong coordination ability with cobalt atoms compared with a commonly used phosphine ligand; and finally, the addition of the activator can further significantly increase the activity of the cobalt catalyst. The hydrogenation reaction condition is mild, the reaction rate is high, substantially no carbonyl hydrogenation side reaction occurs, and the carbonyl compound can be obtained in a high yield.
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Paragraph 0064-0066
(2019/11/20)
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- Rh(III)Cp? and Ir(III)Cp? Complexes of 1-[(4-Methyl)phenyl]-3-[(2-methyl-4′-R)imidazol-1-yl]triazenide (R = t-Bu or H): Synthesis, Structure, and Catalytic Activity
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A series of iridium and rhodium complexes have been synthesized using as ligand a triazenide monofunctionalized with an imidazole substituent. Steric hindrance at the imidazole moiety induced differences in the coordination modes as well in the catalytic behavior of complexes 4-7. Complexes 4-7 were tested in the transfer hydrogenation of acetophenone and 5-alken-2-ones. The hydrogenation of either the double bond or the carbonyl group in 5-alken-2-ones, showed to be selective in the presence of 6, 7, and 10 and has a dependence on the presence or absence of base. Control experiments point out that the imidazole moiety in the structure of complexes 4-7 speeds-up the catalysis.
- Camarena-Diáz, Juan P.,Iglesias, Ana L.,Chávez, Daniel,Aguirre, Gerardo,Grotjahn, Douglas B.,Rheingold, Arnold L.,Parra-Hake, Miguel,Miranda-Soto, Valentín
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p. 844 - 851
(2019/02/19)
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- Phosphonate-Mediated Immobilization of Rhodium/Bipyridine Hydrogenation Catalysts
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RhL2 complexes of phosphonate-derivatized 2,2′-bipyridine (bpy) ligands L were immobilized on titanium oxide particles generated in situ. Depending on the structure of the bipy ligand—number of tethers (1 or 2) to which the phosphonate end groups are attached and their location on the 2,2′-bipyridine backbone (4,4′-, 5,5′-, or 6,6′-positions)—the resulting supported catalysts showed comparable chemoselectivity but different kinetics for the hydrogenation of 6-methyl-5-hepten-2-one under hydrogen pressure. Characterization of the six supported catalysts suggested that the intrinsic geometry of each of the phosphonate-derivatized 2,2′-bipyridines leads to supported catalysts with different microstructures and different arrangements of the RhL2 species at the surface of the solid, which thereby affect their reactivity.
- Forato, Florian,Belhboub, Anouar,Monot, Julien,Petit, Marc,Benoit, Roland,Sarou-Kanian, Vincent,Fayon, Franck,Jacquemin, Denis,Queffelec, Clémence,Bujoli, Bruno
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p. 2457 - 2465
(2018/02/06)
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- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
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Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
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Paragraph 0338
(2019/01/07)
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- The Synthesis of Certain Phomentrioloxin A Analogues and Their Evaluation as Herbicidal Agents
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A series of 28 analogues of the phytotoxic geranylcyclohexentriol (-)-phomentrioloxin A (1) has been synthesized through cross-couplings of various enantiomerically pure haloconduritols or certain deoxygenated derivatives with either terminal alkynes or borylated alkenes. Some of these analogues display modest herbicidal activities, and physiological profiling studies suggest that analogue 4 inhibits photosystem II in isolated thylakoids in vitro.
- Taher, Ehab S.,Guest, Prue,Benton, Amanda,Ma, Xinghua,Banwell, Martin G.,Willis, Anthony C.,Seiser, Tobias,Newton, Trevor W.,Hutzler, Johannes
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p. 211 - 233
(2017/04/26)
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- Wilkinson-Type Immobilized Catalyst on Diamond Nanoparticles for Alkene Reduction
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The immobilization of heterogeneous catalysts on solid support materials is an important task of current catalytic and materials science research. We report here the development of a diamond nanoparticles-based Wilkinson's type catalyst for the reduction of olefins to saturated hydrocarbons. The strategy is based on the formation of rhodium(I)-modified nanodiamonds (NDs–Rh) using a surface-immobilized catechol phosphane ligand, to which rhodium metal centers can be coordinated. The resulting material was characterized by solid-state NMR spectroscopy, X-ray photoelectron spectroscopy, thermogravimetry, and TEM before testing the catalytic efficiency of the catalyst. Excellent hydrogenation efficiency with yields in the range of 85–99 % could be obtained with these new NDs–Rh catalysts, which showed in addition good recyclability without loss of activity.
- Queffélec, Clémence,Schlindwein, Simon H.,Gudat, Dietrich,Silvestre, Virginie,Rodriguez-Zubiri, Mireia,Fayon, Franck,Bujoli, Bruno,Wang, Qi,Boukherroub, Rabah,Szunerits, Sabine
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p. 432 - 439
(2017/02/15)
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- Spata-13,17-diene Synthase—An Enzyme with Sesqui-, Di-, and Sesterterpene Synthase Activity from Streptomyces xinghaiensis
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A terpene synthase from the marine bacterium Streptomyces xinghaiensis has been characterised, including a full structure elucidation of its products from various substrates and an in-depth investigation of the enzyme mechanism by isotope labelling experiments, metal cofactor variations, and mutation experiments. The results revealed an interesting dependency of Mn2+ catalysis on the presence of Asp-217, a residue that is occupied by a highly conserved Glu in most other bacterial terpene synthases.
- Rinkel, Jan,Lauterbach, Lukas,Dickschat, Jeroen S.
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supporting information
p. 16385 - 16389
(2017/12/04)
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- A Lewis Base Catalysis Approach for the Photoredox Activation of Boronic Acids and Esters
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We report herein the use of a dual catalytic system comprising a Lewis base catalyst such as quinuclidin-3-ol or 4-dimethylaminopyridine and a photoredox catalyst to generate carbon radicals from either boronic acids or esters. This system enabled a wide range of alkyl boronic esters and aryl or alkyl boronic acids to react with electron-deficient olefins via radical addition to efficiently form C?C coupled products in a redox-neutral fashion. The Lewis base catalyst was shown to form a redox-active complex with either the boronic esters or the trimeric form of the boronic acids (boroxines) in solution.
- Lima, Fabio,Sharma, Upendra K.,Grunenberg, Lars,Saha, Debasmita,Johannsen, Sandra,Sedelmeier, Joerg,Van der Eycken, Erik V.,Ley, Steven V.
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supporting information
p. 15136 - 15140
(2017/11/20)
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- IMINIUM SALT ORGANOCATALYSTS, METHODS OF MAKING, AND METHODS OF USING
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Aspects of the present disclosure include compositions comprising iminium catalyst, methods of making, methods of using, and the like.
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Page/Page column 37-38
(2018/04/11)
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- Single-Site Cobalt Catalysts at New Zr8(μ2-O)8(μ2-OH)4 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Alkenes, Imines, Carbonyls, and Heterocycles
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We report here the synthesis of robust and porous metal-organic frameworks (MOFs), M-MTBC (M = Zr or Hf), constructed from the tetrahedral linker methane-tetrakis(p-biphenylcarboxylate) (MTBC) and two types of secondary building units (SBUs): cubic M8(μ2-O)8(μ2-OH)4 and octahedral M6(μ3-O)4(μ3-OH)4. While the M6-SBU is isostructural with the 12-connected octahedral SBUs of UiO-type MOFs, the M8-SBU is composed of eight MIV ions in a cubic fashion linked by eight μ2-oxo and four μ2-OH groups. The metalation of Zr-MTBC SBUs with CoCl2, followed by treatment with NaBEt3H, afforded highly active and reusable solid Zr-MTBC-CoH catalysts for the hydrogenation of alkenes, imines, carbonyls, and heterocycles. Zr-MTBC-CoH was impressively tolerant of a range of functional groups and displayed high activity in the hydrogenation of tri- and tetra-substituted alkenes with TON > 8000 for the hydrogenation of 2,3-dimethyl-2-butene. Our structural and spectroscopic studies show that site isolation of and open environments around the cobalt-hydride catalytic species at Zr8-SBUs are responsible for high catalytic activity in the hydrogenation of a wide range of challenging substrates. MOFs thus provide a novel platform for discovering and studying new single-site base-metal solid catalysts with enormous potential for sustainable chemical synthesis.
- Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Urban, Ania,Greene, Francis X.,Lan, Guangxu,Lin, Wenbin
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supporting information
p. 12234 - 12242
(2016/09/28)
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- A novel method for synthesizing methyl heptanone
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The present invention relates to an organic matter synthesis method, particularly to a novel methyl heptanone synthesis method, wherein isovaleraldehyde and acetone are adopted as raw materials and are subjected to an aldol condensation reaction and a hydrogenation reaction through a one-pot method under catalysis of catalysts such as triethylamine and palladium carbon to synthesize the methyl heptanone, a small amount of the by-product methyl isobutyl ketone is subjected to distillation recovery, the recovered product is supplied for other positions, and the catalyst used in the reaction process can be repeatedly applied after being recovered. According to the present invention, the method has characteristics of easy operation, high reaction yield, energy saving and environmental protection, and is suitable for industrial production.
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Paragraph 0033; 0034; 0042; 0044; 0046; 0050; 0052; 0052
(2018/02/04)
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- Long-Range Reactivity Modulations in Geranyl Chloride Derivatives
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Derivatives of geraniol are versatile synthetic intermediates that are useful for synthesizing a variety of terpenoid natural products; however, the results presented herein show that subtle differences in the structures of functionalized geranyl chlorides can significantly impact their abilities to function as effective electrophiles in synthetic reactions. A series of focused kinetics experiments identify specific structure-activity relationships that illustrate the importance not only of steric bulk, but also of electronic effects from distant regions of the molecules that contribute to their overall levels of reactivity. Computational modeling suggests that destabilization of the reactant by filled-filled orbital mixing events in some, but not all, conformations may be a critical contributor to these important electronic effects.
- Reardon, Michael B.,Xu, Muyun,Tan, Qingzhe,Baumgartel, P. George,Augur, Danielle J.,Huo, Shuanghong,Jakobsche, Charles E.
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p. 10964 - 10974
(2016/11/29)
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- An Iminium Salt Organocatalyst for Selective Aliphatic C-H Hydroxylation
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The first examples of catalysis of aliphatic C-H hydroxylation by an iminium salt are presented. The method allows the selective organocatalytic hydroxylation of unactivated 3° C-H bonds at room temperature using hydrogen peroxide as the terminal oxidant. Hydroxylation of an unactivated 2° C-H bond is also demonstrated. Furthermore, improved functional group compatibility over other catalytic methods is reported in the form of selectivity for aliphatic C-H hydroxylation over alcohol oxidation. On the basis of initial mechanistic studies, an oxaziridinium species is proposed as the active oxidant.
- Wang, Daoyong,Shuler, William G.,Pierce, Conor J.,Hilinski, Michael K.
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supporting information
p. 3826 - 3829
(2016/08/16)
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- Ruthenium complexes bearing an unsymmetrical pincer ligand with a 2-hydroxypyridylmethylene fragment: Active catalysts for transfer hydrogenation of ketones
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Five ruthenium(ii) complexes were synthesized, including (HO-C5H3N-CH2-C5H3N-C5H4N)Ru(PPh3)Cl2 (3), [(HO-C5H3N-CH2-C5H3N-C5H4N)Ru(PPh3)2Cl][PF6] (4) and [(HO-C5H3N-CH2-C5H3N-C5H4N)Ru(PPh3)2OH][PF6] (5) bearing an unsymmetrical pincer NNN ligand with a 2-hydroxypyridylmethylene fragment, and [(CH3O-C5H3N-CH2-C5H3N-C5H4N)2Ru][Cl]2 (6) and [(CH3O-C5H3N-CH2-C5H3N-C5H4N)2Ru][PF6]2 (7) containing 2-methoxypyridylmethylene moieties. 4 reacts with H2O at room temperature to give 5 whose crystal structure reveals the existence of intramolecular hydrogen-bonding between its two -OH groups. 3 exhibits high catalytic activity for transfer hydrogenation of ketones.
- Shi, Jing,Hu, Bowen,Gong, Dawei,Shang, Shu,Hou, Guangfeng,Chen, Dafa
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p. 4828 - 4834
(2016/03/19)
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- Scope and mechanism in palladium-catalyzed isomerizations of highly substituted allylic, homoallylic, and alkenyl alcohols
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Herein we report the palladium-catalyzed isomerization of highly substituted allylic alcohols and alkenyl alcohols by means of a single catalytic system. The operationally simple reaction protocol is applicable to a broad range of substrates and displays a wide functional group tolerance, and the products are usually isolated in high chemical yield. Experimental and computational mechanistic investigations provide complementary and converging evidence for a chain-walking process consisting of repeated migratory insertion/β-H elimination sequences. Interestingly, the catalyst does not dissociate from the substrate in the isomerization of allylic alcohols, whereas it disengages during the isomerization of alkenyl alcohols when additional substituents are present on the alkyl chain.
- Larionov, Evgeny,Lin, Luqing,Gune, Laure,Mazet, Clment
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supporting information
p. 16882 - 16894
(2015/01/09)
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- A reusable unsupported rhenium nanocrystalline catalyst for acceptorless dehydrogenation of alcohols through γ-C-H activation
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Rhenium nanocrystalline particles (Re NPs), of 2 nm size, were prepared from NH4ReO4 under mild conditions in neat alcohol. The unsupported Re NPs convert secondary and benzylic alcohols to ketones and aldehydes, respectively, through catalytic acceptorless dehydrogenation (AD). The oxidant- and acceptor-free neat dehydrogenation of alcohols to obtain dihydrogen gas is a green and atom-economical process for making carbonyl compounds. Secondary aliphatic alcohols give quantitative conversion and yield. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Re K-edge X-ray absorption near-edge structure (XANES), and X-ray absorption fine structure (EXAFS) data confirmed the characterization of the Re NPs as metallic rhenium with surface oxidation to rhenium(IV) oxide (ReO2). Isotope labeling experiments revealed a novel γ-CH activation mechanism for AD of alcohols. Active particles: A rhenium nanoparticle (Re NP) catalyst is generated from NH4ReO4 under mild solution conditions in neat 3-octanol at 180°C. The resulting Re NPs catalyze acceptorless dehydrogenation of alcohols through a novel C-H activation pathway, and are fully recyclable. Copyright
- Yi, Jing,Miller, Jeffrey T.,Zemlyanov, Dmitry Y.,Zhang, Ruihong,Dietrich, Paul J.,Ribeiro, Fabio H.,Suslov, Sergey,Abu-Omar, Mahdi M.
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supporting information
p. 833 - 836
(2014/01/23)
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- Continuous flow oxidation of alcohols and aldehydes utilizing bleach and catalytic tetrabutylammonium bromide
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We report a method for the oxidation of a range of alcohols and aldehydes utilizing a simple flow system of alcohols in EtOAc with a stream of 12.5% NaOCl and catalytic Bu4NBr. Secondary alcohols are oxidized to ketones, aldehydes are oxidized directly to methyl esters in the presence of methanol, and benzylic alcohols are oxidized to either benzaldehydes or methyl esters, depending on the conditions used. The reaction conditions are mild and generally provide complete conversion in 5-30 min.
- Leduc, Andrew B.,Jamison, Timothy F.
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supporting information; experimental part
p. 1082 - 1089
(2012/08/27)
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- Ruthenium complexation in an aluminium metal-organic framework and its application in alcohol oxidation catalysis
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A ruthenium trichloride complex has been loaded into an aluminium metal-organic framework (MOF), MOF-253, by post-synthetic modification to give MOF-253-Ru. MOF-253 contains open bipyridine sites that are available to bind with the ruthenium complex. MOF-253-Ru was characterised by elemental analysis, N2 sorption and X-ray powder diffraction. This is the first time that a Ru complex has been coordinated to a MOF through post-synthetic modification and used as a heterogeneous catalyst. MOF-253-Ru catalysed the oxidation of primary and secondary alcohols, including allylic alcohols, with PhI(OAc) 2 as the oxidant under very mild reaction conditions (ambient temperature to 40 C). High conversions (up to >99 %) were achieved in short reaction times (1-3 h) by using low catalyst loadings (0.5 mol % Ru). In addition, high selectivities (>90 %) for aldehydes were obtained at room temperature. MOF-253-Ru can be recycled up to six times with only a moderate decrease in substrate conversion. In the frame: A ruthenium trichloride complex is loaded into an aluminium metal-organic framework by post-synthetic modification (see figure). This material is used in the heterogeneous catalysis of the oxidation of primary and secondary alcohols, including allylic alcohols, with PhI(OAc)2 as the oxidant under mild reaction conditions. High selectivities for aldehydes are obtained at room temperature. Copyright
- Carson, Fabian,Agrawal, Santosh,Gustafsson, Mikaela,Bartoszewicz, Agnieszka,Moraga, Francisca,Zou, Xiaodong,Martin-Matute, Belen
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supporting information
p. 15337 - 15344
(2013/01/15)
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- PROCESS FOR THE MANUFACTURE OF 3,7-DIMETHYL-1-OCTEN-3-OL
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The present invention is directed to a process for the manufacture of 3,7-dimethyl-1-octen-3-ol comprising the following steps: a) hydrogenation of 6-methyl-5-hepten-2-on to 6-methyl-2-heptanon in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of carbon, calcium carbonate and aluminum oxide.b) reaction of 6-methyl-2-heptanon with acetylene to 3,7-dimethyl-1-octin-3-ol in the presence of ammonia and potassium hydroxide and in the absence of any additional organic solvent;c) hydrogenation of 3,7-dimethyl-1-octin-3-ol to 3,7-dimethyl-1-octen-3-ol in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of calcium carbonate, aluminum oxide, silica, porous glass, carbon or graphite, and barium sulphate, with the proviso that the catalyst additionally contains lead when the carrier is calcium carbonate. The present invention is further directed to a process for the manufacture of isophytol and vitamin E, where a thus produced 3,7-dimethyl-1-octen-3-ol is used as starting material.
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Page/Page column 4
(2012/03/12)
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- Synthesis of an ionic paramagnetic ruthenium(III) complex and its application as an efficient and recyclable catalyst for the transfer hydrogenation of ketones
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A novel ionic complex, bis[1-butyl-2-(diphenylphosphanyl)-3- methylimidazolium]tetrachloridoruthenium(III) hexafluorophosphate (2), has been synthesized and fully characterized. The single-crystal X-ray diffraction analysis showed that 2 is composed of an Ru complex cation and PF 6- anion. The cation has a highly symmetrical Ru-centered octahedron geometry with four Cl atoms in the equatorial plane and two imidazolium-substituted phosphane ligands in the axial positions. It exhibits paramagnetism due to the presence of one unpaired electron in the phosphane-ligated low-spin RuIII complex. Complex 2 exhibited good catalytic performance in the transfer hydrogenation of a wide range of ketones by using alcohols as hydrogen donors. Owing to its high polarity, good thermal stability, and insensitivity to moisture and oxygen, complex 2 could be used in six catalytic cycles in the transfer hydrogenation of acetophenone without any obvious loss of activity. A novel ionic complex 2 containing an RuIII cation and PF6- anion has been synthesized. The Ru III cation possesses ideal octahedral geometry and exhibits paramagnetism due to the presence of one unpaired electron in the phosphane-ligated low-spin RuIII complex. Complex 2 proves to be an efficient and recyclable catalyst for the transfer hydrogenation of ketones with alcohols as hydrogen donors. Copyright
- Zhou, Chengliang,Zhang, Jing,Dakovic, Marijana,Popovic, Zora,Zhao, Xiaoli,Liu, Ye
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experimental part
p. 3435 - 3440
(2012/09/08)
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- Organic electrosynthesis using toluates as simple and versatile radical precursors
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The electrolysis of toluate esters leads smoothly to the formation of the radical of the alkyl fragment. This property has been used to develop a new electrochemical deoxygenation reaction. The Royal Society of Chemistry.
- Lam, Kevin,Marko, Istvan E.
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experimental part
p. 95 - 97
(2009/03/11)
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- Nonsteroidal benzophenone-containing analogues of cholesterol
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The four benzophenones, 10-13, containing the natural side chain of cholesterol (1) have been synthesized to explore whether the tetracyclic nucleus of 1 is essential for its biochemical properties. The syntheses of analogues 10, 11, and 13 feature efficient introduction of the alkyl side chain by Suzuki coupling. Preliminary biochemical evaluation of 10 and 12 suggests that the sterol tetracyclic nucleus is not required for biological compatibility with 1.
- Gan, Yonghong,Blank, David H.,Ney, Joshua E.,Spencer, Thomas A.
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p. 5864 - 5869
(2007/10/03)
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- RuHCl(CO)(PPh3)3-catalyzed chemoselective transfer-hydrogenation of enones leading to saturated ketones
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The highly chemoselective transfer-hydrogenation of α,β- unsaturated ketones to give saturated ketones was achieved using RuHCl(CO)(PPh3)3 as a catalyst. In addition to α,β-unsaturated ketones, other enones, containing a remote C=C bond, were also reduced to give saturated ketones in good to excellent yields with high selectivity. Georg Thieme Verlag Stuttgart.
- Doi, Takashi,Fukuyama, Takahide,Horiguchi, Jiro,Okamura, Takahiro,Ryu, Ilhyong
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p. 721 - 724
(2007/10/03)
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- Ruthenium-catalyzed isomerization of alkenol into alkanone in water under irradiation of microwaves
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Ruthenium catalyzed isomerization of alkenol into alkanone through a migration of C-C double bond was performed in water under irradiation of microwaves. When the reaction was performed in deuterium oxide instead of water, the trail of the migration was shown by H-D exchange reaction. Copyright
- Ishibashi, Kenichi,Takahashi, Masaaki,Yokota, Yutaka,Oshima, Koichiro,Matsubara, Seijiro
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p. 664 - 665
(2007/10/03)
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- Process for the production of 6-methylheptanone
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Methylheptanone and corresponding homologous methylketones, in particular phytone and tetrahydrogeranyl acetone, are produced by aldol condensation of isovaleraldehyde or prenal or the corresponding aldehydes with acetone in the presence of a catalyst phase, which contains an aldolizing catalyst and a heterogeneous hydrogenating catalyst.
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- Selective dehydrogenation of alcohols and diols catalyzed by a dihydrido iridium PCP pincer complex
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The PCP pincer complex, IrH2{C6H3-2,6-(CH2P-t-Bu 2)2} (1) catalyzes the transfer dehydrogenation of primary and secondary alcohols. Dehydrogenation occurs across the C - O bond rather than the C - C bonds and the corresponding aldehydes or ketones are obtained as the sole products arising from the dehydrogenation reactions. Methanol is an exception to this pattern of reactivity and undergoes only stoichiometric dehydrogenation with 1 to give the carbonyl complex, Ir(CO){C6H3-2,6-(CH2P-t-Bu2) 2} (2). The products are obtained in nearly quantitative yields when the reactions are carried out in toluene solutions. Under the same conditions, 2,5-hexanediol is converted to the annulated product, 3-methyl-2-cyclopenten-1-one which has been isolated in 91% yield in a preparative scale reaction.
- Morales-Morales,Redon,Wang,Lee,Yung,Magnuson,Jensen
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p. 823 - 829
(2007/10/03)
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- Dynamic kinetic resolution of allylic alcohols mediated by ruthenium- and lipase-based catalysts.
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An enzyme-metal combo reaction has been developed for the dynamic kinetic resolution of allylic alcohols in which racemic substrates are transformed by a lipase and a ruthenium complex in the presence of an acyl donor to allylic acetates of high optical purity in over 80% yield.
- Lee,Huh,Kim,Jung,Koh,Park
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p. 2377 - 2379
(2007/10/03)
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- Identification and total synthesis of a novel dimethylated fatty acid from the caribbean sponge Calyx podatypa
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The dimethylated fatty acid 9,13-dimethyltetradecanoic acid was identified for the first time in nature in the Caribbean sponge Calyx podatypa where it occurs together with the rare 10,13-dimethyltetradecanoic acid. The characterization of the novel compound was accomplished using GC- MS, pyrrolidide derivatization, and a five-step total synthesis starting with 8-bromooctanoic acid. The first racemic total synthesis for the rare 10,13- dimethyltetradecanoic acid is also described.
- Carballeira, Nestor M.,Pagan, Mayra
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p. 666 - 669
(2007/10/03)
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- Process for producing 6-methyl-3-hepten-2-one and 6-methyl-2-heptanone analogues, and process for producing phyton or isophytol
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Provided are a process for producing 6-methyl-3-hepten-2-one by cross aldol condensation carried out while each continuously adding to acetone, isovaleraldehyde and an aqueous alkali containing an alkaline substance; a process for producing a 6-methyl-2-heptanone analogue represented by Formula (1): STR1 wherein n is an integer of 0 or 1 or more; which comprises allowing hydrogen, acetone and an aldehyde represented by Formula (2): STR2 wherein n is as defined above; X and Y each represents a hydrogen atom or they are coupled together to form a carbon-carbon bond; and Z and W each represents a hydrogen atom or they are coupled together to form a carbon-carbon bond; to react in the presence of an aqueous alkali containing an alkaline substance, and a hydrogenation catalyst; and a process for producing phyton or isophytol using the 6-methyl -3-hepten-2-one or the 6-methyl-2-heptanone analogue.
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- Process for producing 6-methylheptan-2-one
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In order to make it possible to produce 6-methylheptan-2-one, which is useful as a material for synthesizing isophytol or as a material for synthesizing fragrances such as tetrahydrolinalool and dihydrogeraniol, efficiently and in an industrially simple manner, isovaleral and acetone are subjected to aldol condensation in the presence of a basic substance to form a condensate which contains 4-hydroxy-6-methylheptan-2-one, and then the condensate is subjected to hydrogenation reaction under a dehydration condition to obtain the 6-methylheptan-2-one.
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- Markovnikov vinylborinates from 9-oxa-10-borabicyclo[3.3.2]decanes
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Alkylborinates 1 react with α-methoxyvinyllithium (LiAMV) to produce stable 'ate' complexes, 2, which undergo BCl3-induced alkyl group migration providing new air-stable vinylborinates, 3. These intermediates which are readily converted to either unsymmetrical 1,1-disubstituted alkenes (7) via the Suzuki-Miyaura coupling or, oxidatively, to methyl ketones, (8), one of which was converted to the antihistaminic drug, metron S, 10.
- Soderquist, John A.,Ramos, Jorge,Matos, Karl
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p. 6639 - 6642
(2007/10/03)
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- Synthesis of vitamin E analogues: Possible active forms of vitamin E
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We synthesized several vitamin E analogues containing oxygenated functional groups in place of the 8-methyl group which is common to all the natural vitamin E congeners, based on the hypothesis that the methyl group might be metabolically oxidized to produce active forms which might have specific functions other than the antioxidant function. All the vitamin E analogues examined had antioxidant activity. 8-[6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman]meth anol (1d) and 2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-6-ol (4d) showed similar activity to α-tocopherol. 6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman-8-carba ldehyde (2d) and 6-hydroxy-2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-8-carb oxylic acid (3d) showed weaker activity than α-tocopherol, but their duration of action, especially that of 3d was considerably longer.
- Fujishima, Toshie,Kagechika, Hiroyuki,Shudo, Koichi
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- Isosteric Compounds according to the Hydride Principle of Grimm in the Range of Linalool Scents
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Substitution of the (CH3)2CH=CH group by (CH3)2C=N in linalool as well as by the (CH3)2CH-CH2 group in linalool and in sila-linalool does not lead to noticeable changes of their scent qualities.On the contrary, substitution of the OH group at the tertiary C atom by NH2 or CH3 - hydride isosteric to OH according to Grimm - affords fishy or etheric instead of the original flowery smells thus indicating a transition to different basic classes of odor.Similar results were obtained with the linalool-like scents of benzyldimethylcarbinol and phenylethyldimethylcarbinol.Therefor the theory of Amoore, after which only shape and size of molecules are ruling their odor qualities, must be called in question. - Keywords: Perfumes; Sila Perfumes; Isosteric Compounds; Silazanes; Olfactoric Theories.
- Wannagat, U.,Damrath, V.,Harder, U.
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p. 1159 - 1170
(2007/10/02)
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- Method of preparing C-18 ketones used in the manufacture of Vitamins E and K
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Methods of forming unsaturated C-18 ketones which can be used in the synthesis of Vitamins E and K1 are disclosed. One procedure involves coupling a C-9 primary allylic halide to a carbonyl-group-containing C-9 terminal alkyne. A second, two-step procedure employs a C-4 bis allylic halide (molar excess) and a carbonyl-group-containing C-9 terminal alkyne to form a C-13 primary allylic halide. The C-13 primary allylic halide can then be converted to the desired C-18 ketone by reaction with 2-methyl-3-butyn-2-ol. Novel C-18 ketones (e.g., 14-hydroxy-6,14-dimethyl-10-methylene-5-pentadecen-7,12-diyn-2-one), C-13 allylic halides (e.g., 10-chloromethyl-6-methyl-5,10-undecadien-7-yn-2-one) and C-9 allylic halides (e.g., 6-chloromethyl-2-methyl-6-hepten-3-yn-2-ol) are formed in the process.
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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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p. 8169 - 8178
(2007/10/02)
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- Functionalisation of Saturated Hydrocarbons. Part IX. Oxidation of Cedrol, β- and γ-Eudesmol, Sclareol, Manoyl Oxide, 1,9-Dideoxyforskolin, Methyl trans-Dihydrojasmonate, and Tetrahydrolinalool by the 'Gif System'
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The oxidation of cedrol (1), β- and γ-eudesmol (6 and 7, resp.), sclareol (14), manoyl oxide (15), 1,9-dideoxyforskolin (22) (+/-)-methyl trans-dihydrojasmonate (28), and tetrahydrolinalool (32), nearly all of natural terpenoid origin, by the 'Gif system' has afforded a number of novel products (3, 11, and 12, 16/17, 18/19, 26, 29-31, and ketones corresponding to 34-35, resp.).The structures of these compounds were established by spectroscopic techniques including 2D-NMR and, where appropriate, by comparison with authentic samples.
- Barton, Derek H. R.,Beloeil, Jean-Claude,Billion, Annick,Boivin, Jean,Lallemand, Jean-Yves,et al.
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p. 2187 - 2200
(2007/10/02)
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- METAL COMPLEXES IN ORGANIC SYNTHESIS-V ALKYLATIONS OF PENTANE-2,4-DIONE WITH ALLYLIC ALCOHOLS UNDER PALLADIUM CATALYSIS
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Pentane-2,4-dione with allylic alcohols or benzyl alcohol with palladium catalysts gives high yields of C-monoalkylated diketones, arising mainly from reaction at the terminal end of the allylic system for alkyl monosubstituted allyl alcohols.The effect of the catalyst on the alcohols has been evaluated; rearrangements and disproportionations have been observed.
- Moreno-Manas, M.,Trius, A.
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p. 3009 - 3016
(2007/10/02)
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- Reactivity of Ketones in Homogeneous Catalytic Hydrogenation with Cationic Rhodium Complexes
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The catalytic hydrogenation of several ketones with cationic rhodium complexes has been investigated at 30 deg C with hydrogen at atmospheric pressure.The rate of the reaction depended very much on the structure of both the ketone and phosphine ligand, with triethylphosphine giving the highest activity among the ligands used.An electron-withdrawing substituent in the ketone was found to increase its reactivity among both alkyl and aryl ketones; the rates of reaction of the former ketones were generally faster.Benzyl methyl ketone showed a very high reactivity among aryl ketones, suggesting that the phenyl group may be in a position to interact with the rhodium atom to enhance the reactivity.Unsaturated ketones are hydrogenated catalytically to yield saturated ketones first, which are further hydrogenated to corresponding saturated alcohols.No trace of unsaturated alcohol was observed in this hydrogenation, even when the hydrogenation rate of the olefinic bond in the unsaturated ketone was much smaller than that of the carbonyl group of the corresponding saturated ketone in the consecutive hydrogenation.The reactivities of ketones are discussed in connection with their co-ordination and the hydrogenation mechanisms.
- Fujitsu, Hiroshi,Matsumura, Eiichi,Takeshita, Kenjiro,Mochida, Isao
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p. 2650 - 2655
(2007/10/02)
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- Structures of Echinoside A and B, Two Antifungal Oligoglycosides from the Sea Cucumber Actinopyga echinites (JAEGER)
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On the basis of chemical and physicochemical evidence, the structures of two antifungal oligoglycosides, echinoside A and B from the sea cucumber Actinopyga echinites (JAEGER), have been elucidated as 5 and 3, respectively.Keywords - sea cucumber; Actinopyga echinites (JAEGER); lanostane-type triterpene; oligoglycoside; 1H-NMR; 13C-NMR; snail enzyme
- Kitagawa, Isao,Inamoto, Tatsuya,Fuchida, Masako,Okada, Shinji,Kobayashi, Motomasa,et al.
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p. 1651 - 1653
(2007/10/02)
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- Activation of Reducing Agents. Sodium Hydride Containing Complex Reducing Agents. 13. Selective Heterogeneous Hydrogenation of Polyfunctional Substrates over Nic
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Preparative-scale heterogeneous hydrogenation over Nic at room temperature and 1 atm are described.It is shown that these catalysts allow the selective hydrogenation of carbon-carbon double bonds in the presence of oxo groups without side reactions.Alkynes and functional alkynes are selectively hydrogenated to the corresponding cis alkenes in high yields.Carbonyl group hydrogenations were also performed in high yields.Selective hydrogenation properties of Nic were exemplified in the steroid series.Finally, it was demonstrated that this new catalyst-preparation concept is not limited to nickel and also applies to the preparation of cobalt and palladium catalysts.
- Gallois, Philippe,Brunet, Jean-Jaques,Caubere, Paul
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p. 1946 - 1950
(2007/10/02)
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