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1.
Charlène Calata 《Tetrahedron》2009,65(20):3967-7404
The study of the Julia-Kocienski reaction between fluorinated arylsulfone and ketones is described. The corresponding fluoroalkenes were isolated in moderate to good yields from β- and δ-substituted cyclic ketones. From acyclic ketones and α-substituted cyclic ketones a decarbethoxylation reaction of the sulfonylesters occurred. This decarbethoxylation reaction opened a new route for the preparation of a variety of fluoroalkylsulfones as potential building blocks for the preparation of fluoroalkenes. 相似文献
2.
Diaryl ketones are reduced selectively to the corresponding benzhydrols in good yield by aluminium powder in the presence of sodium hydroxide in the solvent system MeOH:H2O=2:1 whereas dialkyl ketones, α-tetralone, aryl alkyl ketones and cycloalkanones remain mostly unaffected. Interestingly, diaryl ketones remain totally unchanged by the present reagent combination in the absence of water, that is in anhydrous methanol. 相似文献
3.
Mourad BoukachabiaSaoussen Zeror Jacqueline Collin Jean-Claude FiaudLouisa Aribi Zouioueche 《Tetrahedron letters》2011,52(13):1485-1489
ATH reductions of aliphatic ketones in water catalyzed by ruthenium coordinated by prolinamide ligands produce alcohols with moderate enantiomeric excesses in most cases. A set of seven aliphatic ketones is proposed for a rapid evaluation of the enantioselectivity of catalysts by one-pot multi-substrates reduction. The screening of a library of prolinamides shows that according to the structure of the ketones different ligands give the best asymmetric inductions. 相似文献
4.
n unusual reduction of some aromatic aldehydes, ketones by sodium borohydride was discovered. In a THF/H2O or DMSO/H2O solvent system the aromatic aldehydes, ketones with acyloxy substituent on the ortho-position to the carbonyl group can be reduced to the corresponding alkyl phenols. This unusual reduction is applicable also to the corresponding alcohols of all the above aldehydes, ketones. A putative mechanism was suggested. In addition to the above aldehydes, ketones, benzyl alcohols, certain 4-acyloxybenzyl esters(probably also the 2-substituted analogues) such as 4-benzoyloxybenzyl benzoate was also found to be reduced to methylphenol by this unusual reduction. 相似文献
5.
《高等学校化学研究》1999,(2)
IntroductionAsamildreductant,sodiumborohydride(NaBH4)iswidelyusedinorganicsynthesistopreparealcoholsfromaldehydesandketones.C... 相似文献
6.
A method for the synthesis of 2-naphthols 4 is described. The carbonylative Stille coupling reactions of 2-bromobenzyl bromides with tributylallylstannane to produce 2-bromobenzyl β,γ-unsaturated ketones 2 in satisfactory to excellent yields has been achieved. The isomerization of 2-bromobenzyl β,γ-unsaturated ketones 2 can readily occur under basic conditions to generate 2-bromobenzyl α,β-unsaturated ketones 3. The 2-bromobenzyl α,β-unsaturated ketones 3 can be transformed into 2-naphthols 4 via intramolecular Heck reaction in satisfactory to good yields. 相似文献
7.
Trimethylsilylethynyl ketones can be desilylated in the presence of a tethered carbon diacid and induced to undergo a double Michael reaction in situ. The trimethylsilylethynyl ketones can serve as surrogates of ethynyl ketones that are difficult to prepare or isolate. 相似文献
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9.
Zinc bis-tetrahydroborate forms a solid complex with dimethylformamide (DMF) of composition, Zn(BH4)2 1.5DMF. Unlike zinc bis-tetrahydroborate itself, the complex with DMF can be stored as a solid at room temperature. Ketones and aldehydes are reduced to the corresponding alcohols by the complex but the mechanism of reduction appears to be different from that using zinc bis-tetrahydroborate itself and from other tetrahydroborates in that only one hydride equivalent from each BH4− unit is utilized and not four. Further, although saturated aliphatic ketones are reduced rapidly to alcohols, aromatic ketones react much more slowly and ,β-unsaturated ketones react very slowly so that the complex appears to have selective reducing potential with regard to different classes of ketones. It is also apparent that the zinc bis-tetrahydroborate/DMF complex reduces sterically hindered saturated ketones much more slowly than it does unhindered ketones. An analogous cadmium bis-tetrahydroborate/DMF complex can be prepared in solution and reacts with ketones similarly to the zinc complex. 相似文献
10.
V. Yu. Kuksenok V. V. Shtrykova V. D. Filimonov S. P. Sidel’nikova 《Russian Journal of Organic Chemistry》2016,52(2):196-199
Ketoximes formed from ketones in the presence of hydroxylamine and silica gel in formic acid undergo in situ the Beckmann rearrangement under mild conditions affording in high yields the corresponding amides. Unsymmetrical aromatic ketones, methyl aryl ketones, and methyl cyclohexyl ketone under these conditions form as a rule amides mixtures. 相似文献
11.
Alexander O. Terent’ev Igor B. Krylov Vera A. Vil’ Zhanna Yu. Pastukhova Sergey A. Fastov Gennady I. Nikishin 《Central European Journal of Chemistry》2012,10(2):360-367
It was found that oximes undergo deoximation in the presence of the H2O2aq-HBraq system to form ketones and bromo ketones. This reaction provided the basis for the synthesis of dibromo ketones in yields
varying from 40% to 94%. This method is environmentally friendly, sustainable, and easy to perform. The results of this investigation
extend the potential of the use of oximes for the protection of carbonyl group, thus offering the ability to perform not only
conventional deoximation but also the subsequent bromination of ketones. The reaction is easily scaled up and dibromo ketones
can be prepared in gram amounts.
相似文献
12.
E.M. Gordon Jelka Pluščec N.G. Delaney S. Natarajan J. Sundeen 《Tetrahedron letters》1984,25(31):3277-3280
Amino acid derived chloromethyl ketones are shown to undergo a general dehydrohalogenation reaction under mild, basic, nonnucleophilic conditions to afford α-β-unsaturated ketones. 相似文献
13.
A catalytic cycle which leads to α,-β ethylenic ketones and methyl ketones from terminal alkenes in the presence of palladium trifluoroacetate,oxygen and U.V. light is described. 相似文献
14.
Kloetzing RJ Krasovskiy A Knochel P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(1):215-227
Magnesium alkoxides undergo a hydride-transfer oxidation with benzaldehyde as the oxidant. This magnesium variant of the Oppenauer oxidation was used for the synthesis of polyfunctional biaryl ketones. LiCl was found to promote this reaction by enhancing the solubility of magnesium alkoxides. This mild oxidation method was especially useful for preparing ketones bearing a metallocenyl unit as well as various new ferrocenyl ketones and tricarbonylchromium complexes. This last class of ketones was reduced with the CBS catalyst (CBS=Corey-Bakshi-Shibata, diphenyl oxazaborolidine) to chiral benzhydrol complexes with high enantioselectivity enabling an asymmetric synthesis of electron-rich or -poor benzhydryl alcohols (up to 94 % ee). 相似文献
15.
Gruber CC Oberdorfer G Voss CV Kremsner JM Kappe CO Kroutil W 《The Journal of organic chemistry》2007,72(15):5778-5783
An easy to use computerized algorithm for the determination of the amount of each labeled species differing in the number of incorporated isotope labels based on mass spectroscopic data is described and evaluated. Employing this algorithm, the microwave-assisted synthesis of various alpha-labeled deuterium ketones via hydrogen-deuterium exchange with deuterium oxide was optimized with respect to time, temperature, and degree of labeling. For thermally stable ketones the exchange of alpha-protons was achieved at 180 degrees C within 40-200 min. Compared to reflux conditions, the microwave-assisted protocol led to a reduction of the required reaction time from 75-94 h to 40-200 min. The alpha-labeled deuterium ketones were reduced by biocatalytic hydrogen transfer to the corresponding enantiopure chiral alcohols and the deconvolution algorithm validated by regression analysis of a mixture of labeled and unlabeled ketones/alcohols. 相似文献
16.
Lazny R Nodzewska A Sienkiewicz M Wolosewicz K 《Journal of combinatorial chemistry》2005,7(1):109-116
A new approach to polymeric supports useful for the immobilization of aldehydes and ketones via hydrazone linkers is reported. The new strategy gives supports with better properties and is effective for the synthesis of all supports previously used for the alkylation of ketones anchored as hydrazones. In contrast to other approaches, the new strategy also provided a polymer with an economical C2 spacer linker. The supports were used for immobilization of ketones 3-pentanone, acetone, N-benzylpiperidone, and aldehydes hexanal and 3-phenylpropanal in the form of their hydrazones. The polymer-supported hydrazones were subjected to alpha-alkylation (LDA/RX) followed by acidic, reductive, or oxidative cleavage/workup procedures to provide alpha-alkylated aldehydes or ketones as well as corresponding primary amines, alcohols, nitriles or acids. 相似文献
17.
A basic ionic liquid, 1-methyl-3-butylimidazolium hydroxide, [bmIm]OH, catalyzes the Michael addition of active methylene compounds to conjugated ketones, carboxylic esters and nitriles. It further catalyzes the addition of thiols to α,β-acetylenic ketones and alkylation of 1,3-dicarbonyl and -dicyano compounds. The Michael addition to α,β-unsaturated ketones proceeds in the usual way, giving the monoaddition products, whereas addition to α,β-unsaturated esters and nitriles leads exclusively to the bis-addition products. The α,β-acetylenic ketones undergo double conjugate addition with thiols producing β-keto 1,3-dithio-derivatives. In the alkylation reaction the acyclic 1,3-diketones are monoalkylated, whereas cyclic ketones undergo dialkylation under identical conditions. All these reactions were carried out without any organic solvent. The ionic liquid can also be recycled. 相似文献
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19.
The regiochemistry of ring expansions of 2-substituted cyclic ketones using 1,2-azidoethanol and 1,3-azidopropanol was examined. It was determined that the reactions of ketones with an adjacent methyl or ethyl group are generally unselective, but that bulkier substituents lead to preferential migration of the more highly substituted carbon. In addition, it was found that ketones bearing inductively electron-withdrawing substituents (OMe, Ph, Br) undergo selective migration of the less highly substituted carbon. For some substrates, alternative reaction pathways were also identified. 相似文献
20.
We detail our efforts toward the selective detection of cyclic ketones, e.g. cyclohexanone, a component of plasticized explosives. Thin films comprised of a conjugated polymer are used to amplify the emission of an emissive receptor via energy transfer. We propose that the energy transfer is dominated by an electron-exchange mechanism to an upper excited state of the fluorophore followed by relaxation and emission to account for the efficient energy transfer in the absence of appreciable spectral overlap. Exposure to cyclic ketones results in a ratiometric fluorescence response. The thin films show orthogonal responses when exposed to cyclic ketones versus acyclic ketones. We demonstrate that the exquisite selectivity is the result of a subtle balance between receptor design and the partition coefficient of molecules into the polymer matrix. 相似文献