- ACTIVATION OF REDUCING AGENTS. SODIUM HYDRIDE CONTAINING COMPLEX REDUCING AGENTS 29. EPIMERIZATION OF ALCOHOLS BY NICKEL-CONTAINING COMPLEX REDUCING AGENTS (NiCRA)
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Epimerization of selected alcohols has been easily achieved by nickel-containing Complex Reducing Agents (termed NiCRA) prepared from 2,5-dimethyl-2,5-hexanediol.It is shown that these reactions are under thermodynamic control.
- Feghouli, G.,Vanderesse, R.,Fort, Y.,Caubere, P.
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- Powerful Continuous-Flow Hydrogenation by using Poly(dimethyl)silane-Supported Palladium Catalysts
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We developed poly(dimethyl)silane-supported Pd catalysts that are readily prepared from Pd(OAc)2, poly(dimethyl)silane, and Al2O3. The immobilization was achieved for the first time with a support that does not contain benzene rings. The Pd catalyst thus prepared was found to have higher hydrogenation activity than Pd/C. Furthermore, the catalyst was used in continuous-flow hydrogenation with various substrates, including simple liquid substrates (neat) and dissolved solid substrates. Vegetable oils, squalenes, and phosphatidylcholine were successfully hydrogenated on gram to kilogram scales.
- Kobayashi, Shu,Okumura, Mikiko,Akatsuka, Yuichi,Miyamura, Hiroyuki,Ueno, Masaharu,Oyamada, Hidekazu
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p. 4025 - 4029
(2015/12/26)
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- One-Pot Bi(OTf)catalyzed oxidative deprotection of tert -butyldimethyl silyl ethers with TEMPO and co-oxidants
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A sequential one-pot synthesis for the oxidation of primary and secondary tert-butyldimethylsilyl (TBDMS) ethers, using catalytic amounts of metal triflates and TEMPO in combination with PhIO or PhI(OAc)in THF or acetonitrile, is described. Acid-sensitive protecting groups such as methylidene, isopropylidene, acetals, and Boc are unaffected under the reaction conditions. Another feature of this procedure is its high selectivity for TBDMS ethers over tert-butyldiphenylsilyl ethers and of aliphatic TBDMS groups over phenolic TBDMS groups. Georg Thieme Verlag Stuttgart - New York.
- Barnych, Bogdan,Vatèle, Jean-Michel
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experimental part
p. 2048 - 2052
(2011/10/19)
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- Recyclable gold nanoparticle catalyst for the aerobic alcohol oxidation and C-C bond forming reaction between primary alcohols and ketones under ambient conditions
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A recyclable gold catalyst is synthesized from readily available reagents by immobilizing gold nanoparticles in aluminum oxyhydroxide support through a simple sol-gel method. The catalyst showed the high activity even at room temperature in the aerobic oxidation of various alcohols and in the coupling reaction between primary alcohols and ketones.
- Kim, Sungjin,Bae, Sang Won,Lee, Jae Sung,Park, Jaiwook
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experimental part
p. 1461 - 1466
(2009/04/11)
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- Mild and recyclable hypervalent iodine system for oxidation of alcohols
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A simple and mild system for oxidation of primary and secondary alcohols to corresponding aldehydes and ketones has been developed using 4,4′-bis (dichloroiodo) biphenyl in combination with tetraethylammonium bromide (TEAB) at room temperature. Facile recovery and recyclability of the oxidant is reported. Copyright Taylor & Francis Group, LLC.
- Telvekar, Vikas N.,Herlekar, Omkar P.
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p. 859 - 863
(2007/10/03)
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- Application of the excited state meta effect in photolabile protecting group design
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A novel photolabile protecting group for carbonyl compounds has been developed, based on the excited state meta effect.
- Wang, Pengfei,Hu, Ayou,Wang, Yun
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p. 2831 - 2833
(2008/02/07)
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- Palladium nanoparticles entrapped in aluminum hydroxide: Dual catalyst for alkene hydrogenation and aerobic alcohol oxidation
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(Chemical Equation Presented) A new aluminum hydroxide-supported palladium catalyst (1) made by a one-pot synthesis through nanoparticle generation and gelation shows a dual catalytic activity for olefinic hydrogenation and aerobic alcohol oxidation.
- Min, Serk Kwon,Kim, Namdu,Cheon, Min Park,Jae, Sung Lee,Kyung, Yeon Kang,Park, Jaiwook
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p. 1077 - 1079
(2007/10/03)
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- Chemoselective Reduction of α,βUnsaturated Aldehydes, Ketones, Carboxylic Acids, and Esters with Nickel Boride in Methanol-Water
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A facile procedure for the conjugate reduction of α,β -unsaturated aldehydes, ketones, carboxylic acids, and esters is reported with nickel boride generated in situ from NiCl2·6H 2O/NaBH4 in methanol-water at ambient temperature.
- Khurana, Jitender Mohan,Sharma, Purnima
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p. 549 - 552
(2007/10/03)
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- Pd(II)-hydrotalcite-catalyzed selective oxidation of alcohols using molecular oxygen
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A novel heterogenized Pd catalyst, Pd supported by hydrotalcite [Pd(II)-hydrotalcite], was synthesized by a simple operation from commercially available hydrotalcite, Pd(OAc)2 and pyridine. The catalyst was effective for the oxidation of a wide range of alcohols using molecular oxygen as a sole oxidant. With this catalytic system, various alcohols were readily converted to the corresponding aldehydes or ketones selectively in high to excellent yields. Sterically less hindered substrates were converted to the corresponding ketones much faster than the hindered ones. For example, cyclohexanol was converted to cyclohexanone in 79% yield for 15 hr, while larger-sized cyclic alcohols were oxidized to the corresponding ketones only in 32-77% yields in the same reaction time. The catalyst was also applicable to the oxidation of unsaturated alcohols such as geraniol and nerol without any isomerization of an alkenic part. Modified Pd(II)-hydrotalcite [Pd(II)-hydrotalcite(m)] could be reused several times while keeping its activity.
- Uemura,Kakiuchi,Nishimura,Inoue
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p. 165 - 172
(2007/10/03)
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- Pd(II)-hydrotalcite-catalyzed oxidation of alcohols to aldehydes and ketones using atmospheric pressure of air
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A heterogenized Pd catalyst, Pd(II)-hydrotalcite (palladium(II) acetate-pyridine supported by hydrotalcite) catalyzes the aerobic oxidation in toluene of a variety of primary and secondary alcohols into the corresponding aldehydes and ketones in high yields using atmospheric pressure of air as a sole oxidant under mild conditions. This catalyst is also effective for the oxidation of allylic alcohols, especially such as geraniol and nerol, without any isomerization of an alkenic part. The catalyst can be easily prepared from all commercially available reagents and reused several times.
- Kakiuchi,Maeda,Nishimura,Uemura
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p. 6620 - 6625
(2007/10/03)
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- Palladium(II)-catalyzed oxidation of alcohols to aldehydes and ketones by molecular oxygen
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A novel combination of Pd(OAc)2/pyridine/MS3A catalyzes the aerobic oxidation in toluene of a variety of primary and secondary alcohols into the corresponding aldehydes and ketones in high yields. Various substituents and protecting groups are compatible with this oxidation. The ca. 2:3 ratio of O2 uptake to product yield is observed, whereas in the absence of MS3A, the ratio is ca. 1:1, suggesting the in situ formation of H2O2 and its decomposition by MS3A into water and oxygen. A catalytic cycle including the formation of a Pd(II)-alcoholate followed by β-elimination of a Pd(II)H species and a carbonyl compound and then the formation of a Pd(II)OOH species is proposed.
- Nishimura, Takahiro,Onoue, Tomoaki,Ohe, Kouichi,Uemura, Sakae
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p. 6750 - 6755
(2007/10/03)
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- Synthesis of α,β-unsaturated ketone from α-iodo ketone using photoirradiation
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Irradiation of α-iodo ketone in hexane under a nitrogen atmosphere with a high-pressure mercury lamp (λ>300nm) at room temperature afforded the corresponding α,β-unsaturated ketones in good yield. This reaction affords a new, clean and convenient synthetic method for the α,β-unsaturated ketone.
- Ji, Shun-Jun,Takahashi, Eiji,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
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p. 9263 - 9266
(2007/10/03)
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- Clay supported ammonium nitrate 'clayan' a rapid and convenient regeneration of carbonyls in dry media
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Regeneration of carbonyls from their oximes, phenylhydrazones and tosylhydrazones derivatives using clay supported ammonium nitrate 'clayan' under microwave irridiation is described. The inexpensive reagent and solvent free condition makes the procedure simple and economic.
- Meshram,Srinivas, Dale,Reddy, Gondi Sudershan,Yadav
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p. 4401 - 4408
(2007/10/03)
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- Envirocat EPZG as a New Heterogeneous Catalyst for the Regeneration of Ketones from Their Tosylhydrazones
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Envirocat EPZG represents a new heterogeneous catalyst for ketones regeneration from their tosylhydrazones. Aldehyde tosylhydrazones were less reactive under these conditions, allowing to perform a selective regeneration of ketone in the presence of both ketone and aldehyde tosylhydrazones.
- Ballini, Roberto,Bosica, Giovanna,Maggi, Raimondo,Sartori, Giovanni
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p. 795 - 796
(2007/10/03)
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- An Acylative C-C Single-Bond Cleavage and a Self-Cyclization of Ethyl 2-(Trimethylsilylmethyl)penta-2,4-dienoate or Its Free Acid under Ritter Condition
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An acylative C(3)-C(4)-bond cleavage of ethyl 4,5-disubstituted 2-(trimethylsilylmethyl)penta-2,4-dienoate occurred to give an ethyl 2-(2-oxoalkyl)acrylate by treatment with trifluoromethanesulfonic acid in nitriles. A self-cyclization also occurred to give a 5,5-disubstituted 3-methylenetetrahydrofuran-2-one when the reactions were carried out in bulky nitriles. Only self-cyclization proceeded when the corresponding 4,5-disubstituted 2-(trimethylsilylmethyl)penta-2,4-dienoic acid was treated in acetonitrile. The reaction mechanism is described.
- Kuroda, Chiaki,Mitsumata, Naoko,Tang, Chen Ying
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p. 1409 - 1416
(2007/10/03)
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- Studies on the Oxidation of Alcohols Employing t-Butyl Hydroperoxide (TBHP) and Fe(III) Catalysts.
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New methodology for the oxidation of alcohols to ketones in good yield utilizing catalytic amounts of FeIII salts and TBHP as the oxidant is highlighted.Competition between alcohol and hydrocarbon oxidation has been clearly demonstrated.The "normal" Gif-type solvent system (pyridine/ acetic acid) can be replaced by the alcohol itself.
- Barton, Derek H. R.,Beviere, Stephane D.,Chabot, Beatrice M.,Chavasiri, Warinthorn,Taylor, Dennis K.
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p. 4681 - 4684
(2007/10/02)
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- Al-NiCl(2°)6H2O-THF: A new, mild and neutral system for selective reduction of organic functional groups
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A mild and neutral reducing system consisting of Al-NiCl(2°)6H2O-THF has been developed and reacted with a series of organic compounds containing different functional groups in order to evaluate its synthetic utility. It was observed that this system very efficiently reduces the α-enones to the saturated ketones, aromatic aldehydes and ketones to the corresponding alcohols, nitriles and nitroarenes to amines, acid anhydrides and acid chlorides to aldehydes, disulphides to thiols and epoxides to the corresponding alcohols. On the other hand isolated double bonds, carboxylic acids, esters, lactones, primary, benzyl and allyl halides, aliphatic aldehydes and ketones and aliphatic nitro compounds were found to remain inert to this system. Furthermore, the reducing properties of Al-NiCl(2°)6H2O in several other organic solvents were also studied.
- Sarmah,Barua
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p. 8587 - 8600
(2007/10/02)
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- Electron Transfer Mediated Photoreductions of α,β-Unsaturated Ketones
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The photoreduction of α,β-unsaturated ketones with triethylamine-alcohol solutions yields dihydro- and pinacol products.With 2 to 3 M triethylamine in methanol, the photoreduction occurs with good efficiency.Protonation by methanol of the semi-enone intermediate occurs at the β-carbon to yield the dihydro product.
- Givens, Richard S.,Singh, Rominder,Xue, Jieyou,Park, Young-Hee
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p. 6793 - 6796
(2007/10/02)
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- Highly Selective Heterogeneous Palladium-Catalyzed Hydrogenations Using Triethoxysilane and Water
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Treatment of alkenes or alkynes at ambient temperature with triethoxysilane and 5 mol percent of palladium(II) acetate in a mixture of tetrahydrofuran and water affords the corresponding hydrogenated products.Excellent chemoselectivities and stereoselectivities can be abtained using this process.
- Tour, James M.,Cooper, Joel P.,Pendalwar, Shekhar L.
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p. 3452 - 3453
(2007/10/02)
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- Chromium(VI) or Ruthenium(II) Complex Catalysis in Oxidation of Alcohols to Aldehydes and Ketones by Means of Bis(trimethylsilyl) Peroxide
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Bis(trimethylsilyl) peroxide (BTSP) serves as an effective oxidant of alcohols in the presence of chromium(VI) or ruthenium(II) complexes as catalysts in dichloromethane.Selective oxidation of primary alcohols in preference to secondary ones using RuCl2(PPh3)3 as a catalyst is also described.
- Kanemoto, Shigekazu,Matsubara, Seijiro,Takai, Kazuhiko,Oshimara, Koichiro,Utimoto, Kiitiro,Nozaki, Hitosi
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p. 3607 - 3612
(2007/10/02)
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- OXIDATION OF ALCOHOLS USING DIMETHYL SULFOXIDE AND TRICHLORMETHYL CHLOROFORMATE
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Treatment of structurally diverse alcohols with dimethyl sulfoxide in the presence of trichloromethyl chloroformate (phosgene dimer) and triethylamine efficiently afforded the corresponding aldehydes or ketones in excellent yields.
- Takano, Seiichi,Inomata, Kohei,Tomita, Shun'ichi,Yanase, Masashi,Samizu, Kyiohiro,Ogasawara, Kunio
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p. 6619 - 6620
(2007/10/02)
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- The Chemistry of Pentavalent Organobismuth Reagents. Part 8. Phenylation and Oxidation of Alcohols by Tetraphenylbismuth Esters
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Tetraphenylbismuth trifluoroacetate under neutral or slightly acidic conditions O-phenylates primary alcohols in reasonable (65-75percent) yield, but gives only moderate yields with secondary alcohols and no O-phenylation with tertiary alcohols.An SN2 type mechanism is proposed with attack of oxygen on aryl carbon.In contrast, the reaction of Bi(V) reagents with alcohols under basic conditions gives, exclusively, oxidation, often with benzene as a leaving group.The presence of a Bi(V) intermediate with a bismuth-oxygen bond has been proved in several different ways using n.m.r. spectroscopy.Thus the reactions of alcohols with Bi(V) reagents parallel the corresponding reactions with phenols.
- Barton, Derek H. R.,Finet, Jean-Pierre,Motherwell, William B.,Pichon, Clotilde
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p. 251 - 260
(2007/10/02)
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- ZINC CHLORIDE-MEDIATED CONJUGATE REDUCTION WITH SILICON HYDRIDES AND PALLADIUM(0) CATALYST
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The chemistry of diphenylsilane/Pd(0), a system previously known to reduce only allylic heterosubstituents, has been radically altered by addition of catalytic amounts of zinc chloride, enabling efficient conjugate reduction of α,β-unsaturated ketones and aldehydes.
- Keinan, Ehud,Greenspoon, Noam
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p. 1353 - 1356
(2007/10/02)
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- TRANSITION-METAL CATALYZED OXIDATION OF ALCOHOLS TO ALDEHYDES AND KETONES BY MEANS OF Me3SiOOSiMe3
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Pyridinium dichromate-Me3SiOOSiMe3 system has been found to be effective for the oxidation of alcohols to the corresponding carbonyl compounds.Selective oxidation of primary alcohols in the presence of secondary ones with RuCl2(PPh3)3-Me3SiOOMe3 is also described.
- Kanemoto, Shigekazu,Oshima, Koichiro,Matsubara, Seijiro,Takai, Kazuhiko,Nozaki, Hitosi
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p. 2185 - 2188
(2007/10/02)
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- A Greatly Improved Procedure for Ruthenium Tetraoxide Catalyzed Oxidations of Organic Compounds
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Addition of acetonitrile to the traditional CCl4/H2O solvent system for ruthenium tetraoxide catalyzed oxidations leads to a greatly improved system; some applications to olefins, alcohols, aromatic rings, and ethers are described.
- Carlsen, Per H. J.,Katsuki, Tsutomu,Martin, Victor S.,Sharpless, K. Barry
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p. 3936 - 3938
(2007/10/02)
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- CONVERSION OF THE ALLYLIC AND HOMOALLYLIC STEROIDAL ALCOHOLS TO THE CORRESPONDING SATURATED KETONES BY MEANS OF THE ACTIVATED Ra/Ni
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Conversion of the allylic and homoallilyc alcohols (1) and (2) to the corresponding saturated ketones (3) and (4), by means of the activated Ra/Ni, in the presence of cyclohexanone, was achieved stereospecifically and high yields.
- Forsek, Joze
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p. 1071 - 1074
(2007/10/02)
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- Oxidation of Ketone and Aldehyde Hydrazones, Oximes, and Semicarbazones and of Hydroxylamines and Hydrazo-compounds, using Benzeneselenic Anhydride
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Benzeneseleninic anhydride (1; BSA) is an effective reagent for the mild regeneration of the carbonyl group from ketone phenylhydrazones, p-nitrophenylhydrazones, tosylhydrazones, oximes, and semicarbazones at 40-50 deg C.Tosylhydrazones and oximes of aldehydes are also readily converted into the parent aldehyde.The phenylhydrazone and p-nitrophenylhydrazone derivatives of aldehydes afford ketoazo-compounds.The ketoazo-species could also be prepared by oxidation of the corresponding hydrazide with compound (1).Both aromatic and aliphatic hydrazo-compounds and hydroxylamines can be oxidised to azo- and nitrozo-derivatives respectively.
- Barton, Derek H. R.,Lester, David J.,Ley, Steven V.
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p. 1212 - 1217
(2007/10/02)
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- Molecular Sieve-assisted Oxidations: New Methods for Carbohydrate Derivative Oxidations
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Molecular sieves catalyse pyridinium chlorochromate and pyridinium dichromate oxidation and so give rise to an efficient synthesis of ketonucleosides and ketosugars at room temperature.
- Herscovici, Jean,Antonakis, Kostas
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p. 561 - 562
(2007/10/02)
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- Silanes in Organic Synthesis. 9. Enesilylation as a Method for 1,2-Carbonyl Migration within Ketones and for Conversion to 1,2-Transposed Allylic Alcohols
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Vinylsilanes are shown to be valuable synthetic intermediates in useful transformations of ketones.The epoxidation of vinylsilanes followed by lithium aluminium hydride reduction and oxidation with chromic acid and sulfuric acid in a two-phase (ether/water) system often gives high yields of 1,2-transposed ketones.With singlet oxygen and sequential sodium borohydride reduction, 2-trimethylsilyl alcohols are produced in which the α position of the parent ketone has been regiospecifically oxygenated.Fluoride ion promoted desilylation completes the conversion to the migrated allylic alcohol.
- Fristad, William E.,Bailey, Thomas R.,Paquette, Leo A.
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p. 3028 - 3037
(2007/10/02)
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- OXIDATION OF ALCOHOLS WITH OXOPEROXOBIS-(N-PHENYLBENZOHYDROXAMATO)MOLYBDENUM(VI)
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The title complex oxidizes primary and secondary alcohols to the corresponding carbonyl compounds.Stereoselective epoxidation of allylic alcohols is also described.
- Tomioka, Hiroki,Takai, Kazuhiko,Oshima, Koichiro,Nozaki, Hitosi,Toriumi, Koshiro
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p. 4843 - 4846
(2007/10/02)
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- Oxidation process
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A novel liquid phase oxidation process using silver silicate as the oxidizing agent which is particularly adapted for oxidation of a hydroxy attached to a carbon atom to a carbonyl group.
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