- Self-promoted nucleophilic addition of hexafluoro-2-propanol to vinyl ethers
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In spite of its low nucleophilicity, hexafluoro-2-propanol easily adds to vinyl ethers, without catalyst, to afford a range of hexafluoroisopropyloxy acetals. This addition reaction also occurred in the presence of a competitive, more nucleophilic alcohol
- Di Salvo, Andrea,David, Marc,Crousse, Benoit,Bonnet-Delpon, Daniele
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- Selective hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid derivatives over supported platinum catalysts
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The conversion of 2-furancarboxylic acid (FCA), which is produced by oxidation of furfural, to 5-hydroxyvaleric acid (5-HVA) and its ester/lactone derivatives with H2 was investigated. Monometallic Pt catalysts were effective, and other noble metals were not effective due to the formation of ring-hydrogenation products. Supports and solvents had a small effect on the performance; however, Pt/Al2O3 was the best catalyst and short chain alcohols such as methanol were better solvents. The optimum reaction temperature was about 373 K, and at higher temperature the catalyst was drastically deactivated by deposition of organic materials on the catalyst. The highest yield of target products (5-HVA, δ-valerolactone (DVL), and methyl 5-hydroxyvalerate) was 62%, mainly obtained as methyl 5-hydroxyvalerate (55% yield). The byproducts were mainly ring-hydrogenation compounds (tetrahydrofuran-2-carboxylic acid and its ester) and undetected ones (loss of carbon balance). The catalyst was gradually deactivated during reuses even at a reaction temperature of 373 K; however, the catalytic activity was recovered by calcination at 573 K. The reactions of various related substrates were carried out, and it was found that the O-C bond in the O-CC structure (1,2,3-position of the furan ring) is dissociated before CC hydrogenation while the presence and position of the carboxyl group (or methoxy carbonyl group) much affect the reactivity.
- Asano, Takehiro,Takagi, Hiroshi,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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p. 6133 - 6145
(2019/11/20)
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- The oxidation of primary alcohols to methyl esters and diols to lactones using trichloroisocyanuric acid
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Primary alcohols and diols are easily oxidized to methyl esters by a solution of trichloroisocyanuric acid with methyl alcohol in dichloromethane. In addition, α,ω-diols are also readily oxidized into lactones by refluxing with trichloroisocyanuric acid and pyridine in dichloromethane.
- Hiegel, Gene A.,Gilley, Cynthia B.
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p. 2003 - 2009
(2007/10/03)
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- Method for producing 1,4-butanediol
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A process for preparing 1,4-butanediol and, if desired, gamma-butyrolactone and THF by oxidizing butane or benzene to form a product stream including maleic anhydride, absorbing maleic anhydride from the product stream with a high-boiling inert solvent in an absorption stage to give a liquid absorption product, esterifying the liquid absorption product with a C1-C5 esterifying alcohol in an esterification stage to form an esterification product comprising the corresponding diester and high-boiling inert solvent, then hydrogenating the esterification product to give a hydrogenation product which comprises the products of value, 1,4-butanediol and, if desired, gamma-butyrolactone and tetrahydrofuran and the esterifying alcohol and which is separated by distillation into the products of value and the esterifying alcohol, and recycling the esterifying alcohol to the esterification zone, which comprises separating the esterification product into the diester and the inert solvent by distillation under reduced pressure prior to the hydrogenation, recycling the inert solvent to the absorption stage, and hydrogenating the diester in the liquid phase over a fixed-bed catalyst.
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- Highly efficient and regioselective cyclization catalyzed by titanium silicate-1
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Highly regioselective cyclization of 3,4, 4,5 and 5,6 unsaturated alcohols to tetrahydrofuranols and tetrahydropyranols is reported using the TS-1-H2O2 system for the first time.
- Bhaumik, Asim,Tatsumi, Takashi
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p. 463 - 464
(2007/10/03)
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- REACTION DES VINYLOGUES D'HEMIACETALS ET DE LEURS EQUIVALENTS SYNTHETIQUES SUR LES ETHERS D'ENOLS HETEROCYCLIQUES
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We describe the reaction of hemiacetal vinylogs 2 or their synthetic equivalent with cyclic enol ethers 1 yielding ketoacetals 3.Acidic treatment of these compounds leads to bicyclic heterocycles 8 or enone aldehyde 12 depending on the nature of substituents R1.
- Poirier, Jean-Marie,Dujardin, Gilles
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p. 3337 - 3340
(2007/10/02)
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- INDIRECT ELECTROCHEMICAL α-METHOXYLATION OF ALIPHATIC ETHERS AND ACETALS - REACTIVITY AND REGIOSELECTIVITY OF THE ANODIC OXIDATION USING TRIS(2,4-DIBROMOPHENYL)AMINE AS REDOX CATALYST
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The technically important α-methoxylation of aliphatic ethers and acetals to form mixed acetals respectively aldehydes or ortho-esters can be performed electrochemically at low potentials in methanol solution using an undivided cell and tris(2,4-dibromophenyl)amine as redox catalyst.The regioselectivity is usually considerably higher as compared with direct electrolysis in the abscence of a catalyst.Especially valuable is the method for the regioselective methoxylation of secondary carbon atoms in presence of primary or tertiary ones and of the acetal carbon in 1,3-dioxolanes.The redox catalyst is stable under the reaction conditions so that more than thousand turnovers could be obtained.
- Ginzel, Klaus-Dieter,Steckhan, Eberhard,Degner, Dieter
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p. 5797 - 5806
(2007/10/02)
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- Anodic α-Methoxylation of Aliphatic Saturated Ethers
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The anodic oxidation of aliphatic saturated ethers carried out in a mixed solvent of methanol and acetic acid gave α-methoxylated ethers in much better yields than those obtained by using only methanol as a solvent.
- Shono, Tatsuya,Matsumura, Yoshihiro,Onomura, Osamu,Yamada, Yasufu
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p. 1099 - 1100
(2007/10/02)
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- Photochemically initiated addition of alcohols to ketones: facile photoketalization of cycloalkanones
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Irradiation at 300 nm of cycloalkanones in methanol gives the corresponding ketals in good yields.The results indicate that an excited state of the cycloalkanone is responsible for the facile addition of methanol to the carbonyl group.
- Malatesta, Vincenzo,Jennings, Michael,Hackett, Peter
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p. 366 - 367
(2007/10/02)
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- 2-Alkoxy-tetrahydrofurans via hydroformylation of allylic alcohols
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2-Alkoxytetrahydrofurans are prepared by hydroformylation of an allylic alcohol in the presence of an alkanol and a rhodium hydroformylation catalyst. The products are useful, inter alia, as intermediates in the preparation of butanediols and substituted
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