- Selective aerobic oxidation of activated alkanes with MOFs and their use for epoxidation of olefins with oxygen in a tandem reaction
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MOFs with Cu2+ centers linked to four nitrogen atoms from azaheterocyclic compounds, i.e., pyrimidine [Cu(2-pymo)2] and imidazole [Cu(im)2], are active catalysts for aerobic oxidation of activated alkanes, such as tetralin, cumene and ethylbenzene. Differences in activity among the two MOFs appear to be related to differences in their ability to decompose the hydroperoxide and to coordinate to the resulting radical OH species. Copper ions in [Cu(im)2] can coordinate by expanding their coordination sphere from 4 to 5 in a reversible way, while in the case of [Cu(2-pymo)2] it results in a displacement of one of the pyrimidine ligands. The MOFs can be used in combination with a silylated Ti-MCM-41 to catalyze the epoxidation of olefins with oxygen by means of a tandem reaction in which the MOF produces cumene hydroperoxide, which is used by Ti-MCM-41 to epoxidize the olefin. The Royal Society of Chemistry 2013.
- Luz,Leon,Boronat,Llabres I Xamena,Corma
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Read Online
- Selective aerobic oxidation of allylic alcohols to carbonyl compounds using catalytic Pd(OAc)2: High intramolecular selectivity
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Allylic alcohols were selectively oxidized into aldehydes or ketones using a Pd(OAc)2-Et3N-O2 system. Diols with one allylic function were selectively oxidized, with one of the hydroxyl groups remaining untouched. Georg Thieme Verlag Stuttgart.
- Batt, Frédéric,Bourcet, Emmanuel,Kassab, Youssef,Fache, Fabienne
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Read Online
- Dispersed Ru nanoclusters transformed from a grafted trinuclear Ru complex on SiO2 for selective alcohol oxidation
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Ru nanoclusters (average diameter = 1.3 ± 0.3 nm) were successfully prepared by using a Ru3 cluster Ru3O(CH 3COO)6(H2O)3·(CH 3COO) grafted on a pyridine-functionalized SiO2 surface. The pyridine moiety dispersed on the SiO2 surface spread the Ru 3 cluster, controlling its surface density, and the nanoclusterization of the Ru cluster proceeded on the surface. The structures of the Ru nanoclusters were characterized by means of elemental analysis; thermogravimetric analysis; FT-IR, UV/vis, and solid-state NMR spectroscopy; BET analysis; X-ray photoelectron spectroscopy; X-ray diffraction; transmission electron microscopy; and Ru K-edge X-ray absorption fine structure analysis. It was found that the catalytic activity for the selective oxidation of alcohol to the corresponding aldehyde using O2 highly depended on the dispersion and structures of the Ru particles, and the Ru nanocluster was found to be efficient in the selective oxidation of a variety of alcohols.
- Muratsugu, Satoshi,Lim, Min Hwee,Itoh, Takahiro,Thumrongpatanaraks, Wipavee,Kondo, Mio,Masaoka, Shigeyuki,Andy Hor,Tada, Mizuki
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Read Online
- Ligand coordination sphere effect of Schiff base cis-dioxomolybdenum(VI) complexes in selective catalytic oxidation of alcohols
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Several cis-dioxomolybdenum(VI) complexes with Schiff bases-derived ligands were synthesized and fully characterized. The catalytic performances of these complexes were tested in the alcohol oxidation under solvent-free condition using H2O2 as oxidant giving high results. The influence of the oxygen, sulfur, and nitrogen atom within the coordination sphere around the molybdenum center was studied (S?>?N?>?O). From this study, we suggest that there exists a relationship between the electronegativity of the atom and the catalytic performance in alcohol oxidation.
- Liu, Haiwen,Zhuo, Zihan,Zhang, Yan,Wei, Hang,Zhang, Wenxin,Li, Tong,Mao, Zuodong,Wang, Weili
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p. 1253 - 1261
(2021/08/13)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- Iodine-catalyzed alcohol disproportionation method
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The invention relates to the technical field of catalysis, in particular to an iodine-catalyzed alcohol disproportionation method which comprises the following steps: sequentially adding alcohol, iodine and a solvent into a high-temperature and high-pressure reaction kettle, introducing a certain amount of nitrogen, conducting reacting for a certain time, collecting an organic phase after the reaction is ended, and conducting fractionating to obtain corresponding alkane and aldehyde/ketone. Alcohol disproportionation is efficient and atom-economical conversion without any additional oxidizing agent and reducing agent, and hydrocarbon and aldehyde/ketone molecules which are easy to separate can be formed at the same time. Meanwhile, the method has wide functional group tolerance, various substrate samples including aryl alcohol derivatives, heterocyclic alcohol derivatives, allyl alcohol derivatives and dihydric alcohol are tested, and the result shows that most of the substrate samples show good or extremely good yield.
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Paragraph 0034-0035
(2021/06/13)
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- Selective Aerobic Oxidation of Alcohols with NO3? Activated Nitroxyl Radical/Manganese Catalyst System
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A homogeneous Mn(NO3)2/2,2,6,6-tetramethylpiperidin-1-yl)oxyl/2-picolinic acid catalyst system is highly active and versatile for the selective aerobic oxidation of alcohols (2,2,6,6-tetramethylpiperidin-1-yl)oxyl=TEMPO, 2-picolinic acid=PyCOOH). The catalytic method enables near quantitative conversion of various primary alcohols to the respective aldehydes using a very simple reaction setup and workup. This study presents findings on the catalyst stability and mechanisms of deactivation. The results show that NO3? plays a crucial catalytic role in the reaction as a source of oxygen activating NOx species. Yet, disproportionation of NO3? to the volatile NO2 during the reaction leads to catalyst deactivation under open air conditions. Catalyst deactivation through this route can be overcome by adding a catalytic amount of nitrate salt, for example NaNO3 into the reaction. This stabilizes the Mn(NO3)2/TEMPO/PyCOOH catalyst and enables oxidation of various primary alcohols to the respective aldehydes using low catalyst loadings under ambient conditions. Secondary alcohols can be oxidized with a modified catalyst utilizing sterically accessible nitroxyl radical 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO) instead of TEMPO. At the end of the alcohol oxidation, pure carbonyl products and the reusable catalyst can be recovered simply by extracting with organic solvent and dilute aqueous acid, followed by evaporation of both phases.
- Lagerblom, Kalle,Keskiv?li, Juha,Parviainen, Arno,Mannisto, Jere,Repo, Timo
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p. 2908 - 2914
(2018/05/03)
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- On the Use of Polyelectrolytes and Polymediators in Organic Electrosynthesis
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Although organic electrosynthesis is generally considered to be a green method, the necessity for excess amounts of supporting electrolyte constitutes a severe drawback. Furthermore, the employment of redox mediators results in an additional separation problem. In this context, we have explored the applicability of soluble polyelectrolytes and polymediators with the TEMPO-mediated transformation of alcohols into carbonyl compounds as a test reaction. Catalyst benchmarking based on cyclic voltammetry studies indicated that the redox-active polymer can compete with molecularly defined TEMPO species. Alcohol oxidation was also highly efficient on a preparative scale, and our polymer-based approach allowed for the separation of both mediator and supporting electrolyte in a single membrane filtration step. Moreover, we have shown that both components can be reused multiple times.
- Schille, Benjamin,Giltzau, Niels Ole,Francke, Robert
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supporting information
p. 422 - 426
(2018/02/21)
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- Accessing Frustrated Lewis Pair Chemistry through Robust Gold@N-Doped Carbon for Selective Hydrogenation of Alkynes
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Pyrolysis of Au(OAc)3 in the presence of 1,10-phenanthroline over TiO2 furnishes a highly active and selective Au nanoparticle (NP) catalyst embedded in a nitrogen-doped carbon support, Au@N-doped carbon/TiO2 catalyst. Parameters such as pyrolysis temperature, type of support, and nitrogen ligands as well as Au/ligand molar ratios were systematically investigated. Highly selective hydrogenation of numerous structurally diverse alkynes proceeded in moderate to excellent yield under mild conditions. The high selectivity toward the industrially important alkene substrates, functional group tolerance, and the high recyclability makes the catalytic system unique. Both high activity and selectivity are correlated with a frustrated Lewis pairs interface formed by the combination of gold and nitrogen atoms of N-doped carbon that, according to density functional theory calculations, can serve as a basic site to promote the heterolytic activation of H2 under very mild conditions. This "fully heterogeneous" and recyclable gold catalyst makes the selective hydrogenation process environmentally and economically attractive.
- Fiorio, Jhonatan Luiz,Gon?alves, Renato Vitalino,Teixeira-Neto, Erico,Ortu?o, Manuel A.,López, Núria,Rossi, Liane Marcia
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p. 3516 - 3524
(2018/04/14)
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- Chemoenzymatic one-pot reaction of noncompatible catalysts: Combining enzymatic ester hydrolysis with Cu(i)/bipyridine catalyzed oxidation in aqueous medium
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The combination of chemical catalysts and biocatalysts in a one-pot reaction has attracted considerable interest in the past years. However, since each catalyst requires very different reaction conditions, chemoenzymatic one-pot reactions in aqueous media remain challenging and are limited today to metal-catalysts that display high activity in aqueous media. Here, we report the first combination of two incompatible catalytic systems, a lipase based ester hydrolysis with a water-sensitive Cu/bipyridine catalyzed oxidation reaction, in a one-pot reaction in aqueous medium (PBS buffer). Key to the solution was the compartmentalization of the Cu/bipyridine catalyst in a core-shell like nanoparticle. We show the synthesis and characterization of the Cu/bipyridine functionalized nanoparticles and the application in the oxidation of allylic and benzylic alcohols in aqueous media. Furthermore, the work demonstrates the implementation of a one-pot reaction process with optimized reaction conditions involving a lipase (CAL-B) to hydrolyze various acetate ester substrates in the first step, followed by oxidation of the resulting alcohols to the corresponding aldehydes under aerobic conditions in aqueous media.
- Sand, Henning,Weberskirch, Ralf
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p. 33614 - 33626
(2017/07/12)
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- Method to oxidize alcohols selectively to aldehydes and ketones with heterogeneous supported ruthenium catalyst at room temperature in air and catalyst thereof
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The present invention relates to a method for selectively oxidizing alcohol by using a heterogeneous catalyst for producing aldehyde and ketone in an organic synthesis process used in the laboratory and chemical industries, and a catalytic system thereof. The method can be used as an intermediate product for synthesizing medicine, scent, fragrance, and precise chemical products, and can use a heterogeneous catalyst at room temperature in air by using the catalytic system and producing alcohol and ketone.COPYRIGHT KIPO 2016
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Paragraph 0021; 0022
(2016/10/07)
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- Iron-Catalysed Selective Aerobic Oxidation of Alcohols to Carbonyl and Carboxylic Compounds
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A method for aerobic alcohol oxidation catalysed by Fe(NO3)3/2,2’-bipyridine/TEMPO has allowed highly selective conversion of primary alcohols into either aldehydes or carboxylic acids in one-step. The oxidation of primary alcohols proceeded selectively to aldehydes, as TEMPO was present in the reaction. Nevertheless, the aldehydes were further oxidized into carboxylic acids as the reaction time was extended. Detailed investigation of the reaction suggested, that the deoxygenation of TEMPO into TMP enabled the auto-oxidation of aldehydes to carboxylic acids, which was initially inhibited in the presence of TEMPO. The procedure was also efficient in oxidation of secondary alcohols when TEMPO was replaced by the less sterically hindered ABNO.
- Lagerblom, Kalle,Wrigstedt, Pauli,Keskiv?li, Juha,Parviainen, Arno,Repo, Timo
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p. 1160 - 1165
(2016/11/23)
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- Selective oxidation of styrene catalyzed by cerium-doped cobalt ferrite nanocrystals with greatly enhanced catalytic performance
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The rare earth metal Ce-doped cobalt ferrite samples CexCo1?xFe2O4 (x?=?0.1, 0.3, 0.5) were prepared by the sol–gel autocombustion route. The as-prepared samples were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, ICP–atomic emission spectroscopy, and N2 physisorption. Their catalytic performance was evaluated in oxidation of styrene using hydrogen peroxide (30%) as oxidant. Compared with pristine CoFe2O4, the Ce-doped samples were found to be more efficient catalysts for the oxidation of styrene to benzaldehyde, with greatly enhanced catalytic performance. Especially, when Ce0.3Co0.7Fe2O4 was used as catalyst, 90.3% styrene conversion and 91.5% selectivity for benzaldehyde were obtained at 90?°C for 9?h reaction. The catalyst can be magnetically separated easily for reuse, and no obvious loss of activity was observed when it was reused in five consecutive runs.
- Tong, Jinhui,Li, Wenyan,Bo, Lili,Wang, Huan,Hu, Yusen,Zhang, Zhixia,Mahboob, Abdulla
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p. 474 - 481
(2016/11/18)
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- Bipyridine-functionalized amphiphilic block copolymers as support materials for the aerobic oxidation of primary alcohols in aqueous media
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Amphiphilic block copolymers with 4-methoxy-4′-alkoxybipyridine ligands in the hydrophobic block were synthesized by cationic ring-opening polymerization. The bipyridine moiety was either introduced directly as a 2-oxazoline monomer (P1) or by polymer-analogous coupling to a precursor poly(2-oxazoline) with chloropentyl side chains (PP2-PP7) to prepare the polymer ligands (P2-P7). The polymers were characterized by NMR and SEC measurements to determine polymer composition, molar masses and polydispersities. In water, these polymers form micelles with cmc values ranging from 1.8 to 22 μmol l-1. SAXS and DLS measurements exhibited spherical particles with particle sizes of 8 to 21 nm. Polymers P1-P7 were finally utilized to carry out the aerobic oxidation of primary alcohols, including allylic, benzylic, and aliphatic derivatives at room temperature (T = 20°C) and ambient air in aqueous media indicating higher activities for P2-P7 compared to P1 as a consequence of the different preparation methods. Moreover, product isolation and catalyst recycling can be easily accomplished by solvent extraction five times without significant loss of activity.
- Sand, Henning,Weberskirch, Ralf
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p. 38235 - 38242
(2015/06/30)
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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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- Lipid-derived aldehyde degradation under thermal conditions
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Nucleophilic degradation produced by reactive carbonyls plays a major role in food quality and safety. Nevertheless, these reactions are complex because reactive carbonyls are usually involved in various competitive reactions. This study describes the thermal degradation of 2-alkenals (2-pentenal and 2-octenal) and 2,4-alkadienals (2,4-heptadienal and 2,4-decadienal) in an attempt to both clarify the stability of aldehydes and determine new compounds that might also play a role in nucleophile/aldehyde reactions. The obtained results showed that alkenals and alkadienals decomposed rapidly in the presence of buffer and air to produce formaldehyde, acetaldehyde, and the aldehydes corresponding to the breakage of the carboncarbon double bonds: propanal, hexanal, 2-pentenal, 2-octenal, glyoxal, and fumaraldehyde. The activation energy of double bond breakage was relatively low (~25 kJ/mol) and the yield of alkanals (10-18%) was higher than that of 2-alkenals (~1%). All these results indicate that these reactions should be considered in order to fully understand the range of nucleophile/aldehyde adducts produced.
- Zamora, Rosario,Navarro, José L.,Aguilar, Isabel,Hidalgo, Francisco J.
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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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- METHOD FOR OXIDIZING ALCOHOLS
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A method for oxidizing an alcohol, wherein oxidation is performed in the presence of a compound represented by the following formula (I) and a bulk oxidant, which enables efficient oxidation of secondary alcohols as well as primary alcohols, and can attain high reaction efficiency even when air is used as a bulk oxidant.
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Paragraph 0127; 0128
(2013/06/05)
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- Remarkable solvent, porphyrin ligand, and substrate effects on participation of multiple active oxidants in manganese(III) porphyrin catalyzed oxidation reactions
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The participation of multiple active oxidants generated from the reactions of two manganese(III) porphyrin complexes containing electron-withdrawing and -donating substituents with peroxyphenylacetic acid (PPAA) as a mechanistic probe was studied by carrying out catalytic oxidations of cyclohexene, 1-octene, and ethylbenzene in various solvent systems, namely, toluene, CH 2Cl2, CH3CN, and H2O/CH 3CN (1:4). With an increase in the concentration of the easy-to-oxidize substrate cyclohexene in the presence of [(TMP)MnCl] (1 a) with electron-donating substituents, the ratio of heterolysis to homolysis increased gradually in all solvent systems, suggesting that [(TMP)Mn-OOC(O)R] species 2 a is the major active species. When the substrate was changed from the easy-to-oxidize one (cyclohexene) to difficult-to-oxidize ones (1-octene and ethylbenzene), the ratio of heterolysis to homolysis increased a little or did not change. [(F20TPP)Mn-OOC(O)R] species 2 b generated from the reaction of [(F20TPP)MnCl] (1 b) with electron-withdrawing substituents and PPAA also gradually becomes involved in olefin epoxidation (although to a much lesser degree than with [(TMP)Mn-OOR] 2 a) depending on the concentration of the easy-to-oxidize substrate cyclohexene in all aprotic solvent systems except for CH3CN, whereas MnV=O species is the major active oxidant in the protic solvent system. With difficult-to-oxidize substrates, the ratio of heterolysis to homolysis did not vary except for 1-octene in toluene, indicating that a MnV=O intermediate generated from the heterolytic cleavage of 2 b becomes a major reactive species. We also studied the competitive epoxidations of cis-2-octene and trans-2-octene with two manganese(III) porphyrin complexes by meta-chloroperbenzoic acid (MCPBA) in various solvents under catalytic reaction conditions. The ratios of cis- to trans-2-octene oxide formed in the reactions of MCPBA varied depending on the substrate concentration, further supporting the contention that the reactions of manganese porphyrin complexes with peracids generate multiple reactive oxidizing intermediates. Copyright
- Hyun, Min Young,Jo, Young Dan,Lee, Jun Ho,Lee, Hong Gyu,Park, Hyun Min,Hwang, In Hong,Kim, Kyeong Beom,Lee, Suk Joong,Kim, Cheal
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supporting information
p. 1810 - 1818
(2013/03/13)
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- Oxidation of alcohols to carbonyl compounds with diisopropyl azodicarboxylate catalyzed by nitroxyl radicals
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A nitroxyl-radical-catalyzed oxidation of alcohols using diisopropyl azodicarboxylate (DIAD) as the terminal oxidantis reported. A variety of primary and secondary alcohols including aliphatic, benzylic, and allylic alcohols are efficiently oxidized to their corresponding aldehydes and ketones without overoxidation to carboxylic acid. 1,2-Diols are oxidized to hydroxyl ketones or diketones depending on the amount of DIAD used.
- Hayashi, Masaki,Shibuya, Masatoshi,Iwabuchi, Yoshiharu
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experimental part
p. 3005 - 3009
(2012/05/04)
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- Efficient and selective oxidation of primary and secondary alcohols using an iron(III)/phenanthroline complex: Structural studies and catalytic activity
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An efficient catalytic system for the oxidation of alcohols has been developed by using iron(III) catalyst [Fe(phen)2Cl 2]NO3 (1) (phen = 1,10-phenanthroline) and H 2O2 as terminal oxidant. A series of primary and secondary alcohols were oxidized into aldehydes and ketones in good yields and excellent selectivities after a short reaction time. The mononuclear iron(III) complex [Fe(phen)2Cl2]NO3 was characterized by several independent methods. The X-ray structure shows distorted octahedral geometry around the FeIII center, which is in a high-spin state (S = 5/2) according to Moessbauer study. Copyright
- Biswas, Bhaskar,Kole, Niranjan,Al-Hunaiti, Afnan,Raeisaenen, Minna T.,Ansalone, Simone,Leskelae, Markku,Repo, Timo,Chen, Yen-Tung,Tsai, Hui-Lien,Naik, Anil D.,Railliet, Antoine P.,Garcia, Yann,Ghosh, Rajarshi
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p. 4479 - 4485,7
(2020/08/24)
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- Structure and characteristics of chitosan cobalt-containing hybrid systems, the catalysts of olefine oxidation
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Cobalt-containing hybrid organo-inorganic materials based on the chitosan-SiO2, chitosan-Al2O3, and chitosan-cellulose systems were obtained. The surface structure and processes that occur during the formation of metal-containing materials, the catalytic properties of which were studied in the oxidation reactions of alkene, were investigated by EPR spectroscopy using a stable pH-sensitive nitroxyl radical, 4-dimethylamino-2-ethyl-5,5-dimethyl-2-(pyridin-4-yl)-2,5-dihydro-1H-imidazole- 1-oxyl, as the adsorbed probe molecules.
- Mekhaev,Pestov,Molochnikov,Kovaleva,Pervova,Yaltuk, Yu. G.,Grigor'Ev,Kirilyuk
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experimental part
p. 1155 - 1161
(2011/08/05)
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- REGENERATION OF A HYDROFORMYLATION CATALYST DURING HYDROFORMYLATION
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A method for hydroformylating or hydrocarbonylating a substrate having a carbon-carbon double or triple bond or both is described. The method comprises exposing the substrate to a hydroformylation catalyst under an atmosphere comprising carbon monoxide and hydrogen in the presence of a regeneration reagent so as to form a product. The regeneration reagent is such that it is capable of at least partially reversing poisoning of the hydroformylation catalyst by a diene or an alkyne or both.
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Page/Page column 16-17
(2011/04/14)
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- New route for the synthesis of benzimidazoles by a one-pot multistep process with mono and bifunctional solid catalysts
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One-pot multistep reactions involving a new environmentally friendly catalytic procedure have been developed for the synthesis of benzimidazoles. Benzimidazole derivatives with biological and pharmaceutical interest have been prepared by a one-pot four step process with a solid catalyst containing basic and oxidation sites. The four steps refer to: (a) oxidation of the alcohol; (b) cyclocondensation of the aldehyde formed with ortho-phenylenediamines, (c) oxidation of the carbon-nitrogen bond, (d) N-alkylation reaction. The process is illustrated by the synthesis of 1,2-disubstituted benzimidazole derivative with antiviral activity.
- Ruiz, Violeta R.,Corma, Avelino,Sabater, María J.
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experimental part
p. 730 - 735
(2010/09/11)
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- PpoC from Aspergillus nidulans is a fusion protein with only one active haem
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In Aspergillus nidulans Ppos [psi (precocious sexual inducer)-producing oxygenases] are required for the production of so-called psi factors, compounds that control the balance between the sexual and asexual life cycle of the fungus. The genome of A. nidulans harbours three different ppo genes: ppoA, ppoB and ppoC. For all three enzymes two different haem-containing domains are predicted: a fatty acid haem peroxidase/ dioxygenase domain in the N-terminal region and a P450 haem-thiolate domain in the C-terminal region. Whereas PpoA was shown to use both haem domains for its bifunctional catalytic activity (linoleic acid 8-dioxygenation and 8-hydroperoxide isomerization), we found that PpoC apparently only harbours a functional haem peroxidase/dioxygenase domain. Consequently, we observed that PpoC catalyses mainly the dioxygenation of linoleic acid (18:2Δ 9Z,12Z), yielding 10-HPODE (10-hydroperoxyoctadecadienoic acid). No isomerase activity was detected. Additionally, 10-HPODE was converted at lower rates into 10-KODE (10-keto-octadecadienoic acid) and 10-HODE (10-hydroxyoctadecadienoic acid). In parallel, decomposition of 10-HPODE into 10-ODA (10-octadecynoic acid) and volatile C-8 alcohols that are, among other things, responsible for the characteristic mushroom flavour. Besides these principle differences we also found that PpoA and PpoC can convert 8-HPODE and 10-HPODE into the respective epoxy alcohols: 12,13-epoxy-8-HOME (where HOME is hydroxyoctadecenoic acid) and 12,13-epoxy-10-HOME. By using site-directed mutagenesis we demonstrated that both enzymes share a similar mechanism for the oxidation of 18:2Δ9Z,12Z; they both use a conserved tyrosine residue for catalysis and the directed oxygenation at the C-8 and C-10 is most likely controlled by conserved valine/leucine residues in the dioxygenase domain. The Authors Journal compilation
- Brodhun, Florian,Schneider, Stefan,Goebel, Cornelia,Hornung, Ellen,Feussner, Ivo
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experimental part
p. 553 - 565
(2011/02/23)
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- Thieme chemistry journal awardees - Where are they now? aldol synthesis by anti-markovnikov hydration of propargyloxy substrates: Feasibility, stereospecifity, and reiterative alkynylation-hydration
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Aldol derivatives have been synthesized by redox-neutral catalytic anti-Markovnikov hydration of propargyloxy sub-strates. A reiterative sequence of aldehyde alkynylation and alkyne hydration leads to 1,3-polyol derivatives. Georg Thieme Verlag Stuttgart.
- Hintermann, Lukas,Kribber, Thomas,Labonne, Aurélie,Paciok, Eva
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scheme or table
p. 2412 - 2416
(2009/12/08)
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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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- Model studies on the degradation of phenylalanine initiated by lipid hydroperoxides and their secondary and tertiary oxidation products
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The reaction of methyl 13-hydroperoxyoctadeca-9,11-dienoate (MeLOOH), methyl 13-hydroperoxyoctadeca-9,11,15-trienoate (MeLnOOH), methyl 13-hydroxyoctadeca-9,11-dienoate (MeLOH), methyl 13-oxooctadeca-9,11-dienoate (MeLCO), methyl 9,10-epoxy-13-hydroxy-11-octadecenoate (Me-LEPOH), and methyl 9,10-epoxy-13-oxo-11-octadecenoate (MeLEPCO) with phenylalanine was studied to determine the comparative reactivity of primary, secondary, and tertiary lipid oxidation products in the Strecker degradation of amino acids. All assayed lipids were able to degrade the amino acid to a high extent, although the lipid reactivity decreased slightly in the following order: MeLEPCO ≥ MeLCO > MeLEPOH ≥ MeLOH > MeLOOH ≈ MeLnOOH. These data confirmed the ability of many lipid oxidation products to degrade amino acids by a Strecker-type mechanism and suggested that, once the lipid oxidation is produced, a significant Strecker degradation of surrounding amino acids should be expected. The contribution of different competitive mechanisms to this degradation is proposed, among which the conversion of the different lipid oxidation products assayed into the most reactive MeLEPCO and the fractionation of long-chain primary and secondary lipid oxidation products into short-chain aldehydes are likely to play a major role.
- Zamora, Rosario,Gallardo, Emerenciana,Hidalgo, Francisco J.
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experimental part
p. 7970 - 7975
(2010/03/30)
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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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- Highly selective aerobic oxidation of alcohol catalyzed by a Gold(I) complex with an anionic ligand
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Highly selective aerobic oxidation of alcohols to carbonyl compounds was catalyzed by a gold(I) complex with an anionic ligand in solution. Copyright
- Guan, Bingtao,Xing, Dong,Cai, Guixing,Wan, Xiaobin,Yu, Nan,Fang, Zhao,Yang, Liping,Shi, Zhangjie
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p. 18004 - 18005
(2007/10/03)
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- Efficient transformation of propargylic alcohols to α,β-unsaturated aldehydes catalyzed by ruthenium/water under neutral conditions
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α,β-Unsaturated aldehydes were selectively obtained in high yields from propargylic alcohols in aqueous solutions using RuCpCl(PR3)2 (Cp=η5-C5H5) as a catalyst. Of the tert-phosphine ligands examined, PMe3 gave the most satisfactory results. Typically, RuCpCl(PMe3)2 (5 mol%) catalyzed the transformation of oct-1-yn-3-ol at 100°C to give 2-octenal in an isolated yield of 85% (E/Z=80/20).
- Suzuki, Toshiaki,Tokunaga, Makoto,Wakatsuki, Yasuo
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p. 7531 - 7533
(2007/10/03)
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- Identification of potent odorants formed by autoxidation of arachidonic acid: Structure elucidation and synthesis of (E,Z,Z)-2,4,7-tridecatrienal
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The aroma composition of autoxidized arachidonic acid was characterized by aroma extract dilution analysis. The most potent odorant was trans-4,5-epoxy-(E)-2-decenal followed by 1-octen-3-one, (E,Z)-2,4-decadienal, (E,Z,Z)-2,4,7-tridecatrienal, (E,E)-2,4-decadienal, and hexanal. (E,Z,Z)-2,4,7-Tridecatrienal was unequivocally identified by mass spectrometry and nuclear magnetic resonance (NMR) data. The stereochemistry of its extended double-bond system was elucidated on the basis of NMR measurements. The target compound was synthesized in four steps starting with bromination of 2-octyn-1-ol, followed by copper-catalyzed coupling of the bromide with ethyl-magnesium bromide and (E)-2-penten-4-yn-1-ol. Partial hydrogenation of the resulting C13-compound with triple bonds in the positions C-4 and C-7 gave rise to (E,Z,Z)-2,4,7-tridecatrien-1,ol, which was finally oxidized to the target compound. It exhibits a typical egg-white-like, marine-like odor at low concentrations, and an intense orange-citrus, animal-like odor at higher concentrations. Its odor threshold was estimated by gas chromatography-olfactometry to be 0.07 ng/L air, Which is of the same order of magnitude as that reported for 1-octen-3-one and (E,E)-2,4-decadienal.
- Blank,Lin,Vera,Welti,Fay
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p. 2959 - 2965
(2007/10/03)
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- Synthetic utility of o-carborane: novel protective group for aldehydes and ketones
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o-Carborane acts as a novel protective group of carbonyl compounds. The reaction of lithiocarborane 2, which was prepared in an essentially quantitative yield from o-carborane and n-butyllithium, with aldehydes or ketones 1 gave the corresponding addition products, o-carboranyl methanol derivatives 3, in high yields. Cleavage of o-carborane from 3 was carried out by treating 3 with catalytic amounts of KOH in THF/H20 (100/1), giving the corresponding aldehydes or ketones in good to high yields along with recovered o-carborane. Accordingly, o-carborane may be utilized as a protective group stable under protic and Lewis acid conditions. Selective alkylation of an ester group, selective reduction of an ester, and selective alkylation of a ketone in the presence of an aldehyde are accomplished by using o-carborane protective groups. - Keywords: o-Carborane; Protective group; Carbonyl compounds
- Nakamura, Hiroyuki,Aoyagi, Kouichi,Yamamoto, Yoshinori
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p. 107 - 115
(2007/10/03)
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- Synthesis of α,β-unsaturated aldehydes and methyl carboxylic esters from 2-acetylenic phenyl sulfides
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2-Alkynylthio benzenes were reduced to 2-Alkenylthio benzenes with diisobutyl aluminum hydride. Mono chlorination of these compounds with sulfuryl chloride and pyridine followed by hydrolysis, in the presence of Cu(II) salts, gave α,β-unsaturated aldehydes. 2-Alkynylthio benzenes were converted into 2-Alkynyl 1,1-bis thiobenzenes by monochlorination with sulfuryl chloride and pyridine followed by treatment with thiophenol and triethylamine. These substances were then converted to α,β-unsaturated methyl carboxylic esters by way of isomerization with sodium methoxide to the corresponding allene and treatment with hydrochloric acid and methanolysis in the presence of iodine.
- Fortes, Carlos C.,Garrote, Clevia F. D.
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p. 3917 - 3941
(2007/10/03)
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- Shape-selective isomerisation of α-acetylenic alcohols to α,β-ethylenic carbonyl compounds by vanadium-pillared montmorillonite catalyst
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A very simple, convenient method for an efficient shape-selective isomerisation of acyclic and aromatic α-acetylenic alcohols only, to the corresponding α,β-ethylenic carbonyl compounds, leaving the cyclic ones unreacted using catalytic amounts of vanadium-pillared montmorillonite catalyst, having -Si-O-V=0 groups with successful reusability is described.
- Choudary,Durga Prasad,Valli
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p. 7521 - 7522
(2007/10/02)
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- A Simple Route to α,β-Unsaturated Aldehydes from Prop-2-ynols
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2-Ynols can be isomerised stereoselectively to (2E)-enals with a ruthenium complex as catalyst.
- Ma, Dawei,Lu, Xiyan
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p. 890 - 891
(2007/10/02)
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- CONVERSION OF α ACETYLENIC ALCOHOLS INTO αβ UNSATURATED ALDEHYDES
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Very mild conditions have been found for the efficient regioselective addition of phenylthiol to ethynyl carbinols.A biphasic aqueous acid hydrolysis then leads to αβ-unsaturated aldehydes.The Meyer-Schuster rearrangement is thus brought about in two steps.
- Julia, Marc,Lefebvre, Christian
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p. 189 - 192
(2007/10/02)
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- Zr-CATALYZED OXIDATION OF ALCOHOLS TO ALDEHYDES IN THE PRESENCE OF t-BuOOH. HIGH REACTIVITY FOR PRIMARY AND ALLYLIC HYDROXYL FUNCTIONS
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ZrO(OAc)2 catalyzes selective oxidation of primary alcohols to aldehydes without formation of carboxylic acids and also chemoselective oxidation of allylic alcohols to α,β-unsaturated aldehydes in the presence of t-BuOOH.
- Kaneda, Kiyotomi,Kawanishi, Yasuyuki,Teranishi, Shiichiro
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p. 1481 - 1482
(2007/10/02)
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- HYDROGEN TRANSFER REACTION OF ALLYLIC ALCOHOLS CATALYZED BY A MOLYBDENUM COMPLEX
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Allylic alcohols undergo hydrogen transfer reactions in the presence of a catalytic amount of the dinitrogen complex trans-Mo(N2)2(dppe)2 (dppe = Ph2PCH2CH2PPh2).From the acyclic allylic alcohols, saturated carbonyl compounds were obtained as the main products whereas from the cyclic allylic alcohols, unsaturated ketones and saturated alcohols were formed predominantly.Accompanying the hydrogen transfer reaction, a decarbonylation reaction occurred simultaneously to give a molybdenum carbonyl complex, cis-(Mo(CO)2(dppe)2 as well as the hydrocarbon in certain cases.The mechanisms of both reactions are discussed.
- Lin, Yingrui,Lu, Xiyan
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p. 321 - 326
(2007/10/02)
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- Reactions with Phosphine Alkylenes, 44. A Further Synthesis of (Z)-α,β-Unsaturated Aldehydes
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Reaction of phosphorus ylides 4, especially such with electron donating groups R, with the glyoxal semiacetal 5 leads Z-stereospecifically to the formation of the acetals 3, which can be cleaved to the (Z)-α,β-unsaturated aldehydes 6.
- Bestmann, Hans Juergen,Ermann, Peter
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p. 3264 - 3266
(2007/10/02)
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- Cumulated Ylides, XII. A Stereoselective Synthetic Method for (Z)-α,β-Unsaturated Aldehydes
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(2-Ethoxyvinyl)triphenylphosphonium bromide (5) is converted with sodium amide into the corresponding phosphaallenylide 6 which adds ethanol forming the ylide 7. 7 is also obtained by the reaction of 5 with sodium ethanolate.The Wittig reaction of 7 with aldehydes 2 proceeds with high (Z)-stereoselectivity to give (Z)-α,β-unsaturated acetals 8 which are cleaved under well defined conditions with p-toluenesulfonic acid or with wet silica gel to (Z)-α,β-unsaturated aldehydes 9.
- Bestmann, Hans Juergen,Roth, Kurt,Ettlinger, Manfred
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p. 161 - 171
(2007/10/02)
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- A Novel Stereoselective Synthesis of the "Pear Ester" Ethyl (2E,4Z)-2,4-Decadienoate
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The title compound 8 is prepared by two stereoselective Wittig olefinations.
- Bestmann, Hans Juergen,Suess, Joachim
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p. 363 - 365
(2007/10/02)
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- A NEW SYNTHESIS OF UNSATURATED ALDEHYDES
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Treatment of 3-trimethylsilylallylic alcohols with phenylsulphenyl chloride gives unstable allylic sulphoxides which rearrange and are then hydrolysed to unsaturated aldehydes.
- Cutting, Ian,Parsons, Philip J.
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p. 2021 - 2022
(2007/10/02)
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- Synthesis of (+/-)-Dictyoprolene
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2-Octyn-1-ol (II) on hydrogenation over Lindlars' catalyst gives (Z)-2-octen-1-ol (III) which on treatment with Corey's reagent provides (Z)-2-octenal (IV).Wittig reaction of methoxymethylenetriphenylphosphorane on IV yields the diene (V) which in turn furnishes 1,1-ethylenedioxynon-3(Z)-ene (VI) in good yield upon refluxing with ethylene glycol/PTS in benzene.Deketalization of VI with PTS in aq. acetone affords the aldehyde (VII).Grignard reaction on VII with vinylmagnesium bromide in anhyd. tetrahydrofuran gives undeca-1,5(Z)-dien-3-ol (VIII) which on acetylation using acetic anhydride/pyridine furnishes (+/-)-dictyoprolene (I).
- Vig, O.P.,Sharma, M.L.,Verma, N.K.,Malik, Neera
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p. 104 - 105
(2007/10/02)
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