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1.
《Tetrahedron: Asymmetry》2001,12(9):1389-1394
Chiral alcohols available in both enantiomeric forms have been tested for the diastereoselective photochemical deconjugation of 2,4-dimethylpentenoic acid esters. (R)-Pantolactone afforded selectively the (2R)-β,γ-unsaturated ester in good yield and high d.e. (89%), while analogous use of (S)-pantolactone gave the (2S)-stereoisomer with similar selectivity. 相似文献
2.
E. I. Klimova E. A. Vazquez Lopez T. Klimova M. Martinez Garcia Ortega S. Hernandez L. Ruiz Ramirez 《Russian Journal of General Chemistry》2004,74(11):1757-1762
Ferrocenyltetrahydropyrimidin-2-ones were prepared by reactions of linear and cyclic ,-unsaturated ketones of the ferrocene series with urea in i-PrOH in the presence of t-BuOK. The structures of the compounds prepared were studied by 1H and 13C NMR and IR spectroscopy, and also by single crystal X-ray diffraction.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1887–1893.Original Russian Text Copyright © 2004 by E. Klimova, Lorez, T. Klimova, Garcia, Hernandez, Ramirez.This revised version was published online in April 2005 with a corrected cover date. 相似文献
3.
《Tetrahedron: Asymmetry》1998,9(5):791-796
The lipase-catalyzed kinetic resolutions of the α,β-unsaturated α′-acetoxy ketones 3a,b have been investigated. Of the lipases examined, CAL-B from Candida antarctica (fraction B) has been shown to be an efficient biocatalyst, which may be used effectively in preparative scale reactions. 相似文献
4.
《Journal of organometallic chemistry》1987,327(2):269-273
α,β-Unsaturated ketones have been hydrogenated inthe presence of HRuCl-(TBPC)2 (TBPC = (−)-trans-1,2-bis(diphenylphosphinomethyl)cyclobutane) to give ketones with a maximum optical purity of 62%. Factors affecting the stereoselectivity of the catalytic reaction are discussed. 相似文献
5.
Nishimura T Sawano T Ou K Hayashi T 《Chemical communications (Cambridge, England)》2011,47(36):10142-10144
Catalytic addition of silylacetylenes to α,β-unsaturated ketones proceeded in the presence of a cobalt complex coordinated with a bisphosphine ligand to give high yields of β-alkynylketones. 相似文献
6.
《Tetrahedron letters》1987,28(39):4591-4592
α,β-Unsaturated ketones dimerize in the presence of catalytic amount of 1,4-diazabicyclo[2.2.2]octane(DABCO) to produce the corresponding 2-methylene-1,5-diketones in good yields. Acrylonitrile provides the corresponding dimerized product. 相似文献
7.
The reactions of ,-unsaturated trifluoromethyl ketones containing aromatic and heteroaromatic substituents with 1-morpholinocyclopentene, 1-morpholinocyclohexene, and 1-methyl-4-morpholino-1,2,5,6-tetrahydropyridine were studied. The reactions proceeded stereospecifically to give the corresponding bicyclo[3.2.1]octane, bicyclo[3.3.1]nonane, and azabicyclo[3.3.1]nonane derivatives. 相似文献
8.
Elinson M. N. Feducovich S. K. Zaimovskaya T. A. Dorofeev A. S. Vereshchagin A. N. Nikishin G. I. 《Russian Chemical Bulletin》2003,52(4):998-1002
Electrolysis of dialkyl ketones in MeOH in the presence of the NaI—NaOH mediator system placed in an undivided cell involves a process analogous to the Favorsky rearrangement of ,-dihalodialkyl ketones giving rise to methyl esters of ,-unsaturated carboxylic acids in 70—75% substance yields and 60—70% current yields. 相似文献
9.
I. N. Klochkova A. A. Anis’kov M. P. Shchekina S. V. Chuvaikina K. A. Andreev 《Russian Journal of Organic Chemistry》2013,49(9):1344-1347
Carbocyclization of unsymmetrical 1,5-diarylpenta-1,4-dien-3-ones with thiobarbituric acid afforded previously unknown 7,11-diaryl-3-thioxo-2,4-diazaspiro[5.5]undecane-1,5,9-triones with high regio- and stereoselectivity. The same spiro compounds were also synthesized by three-component condensation of thiobarbituric acid with the corresponding aromatic aldehydes and 4-arylbut-3-en-2-ones. 相似文献
10.
The one-pot Darzens condensation of α,β-unsaturated aldehydes and ketones with enolates of an α-bromo ester or ketone is described. 相似文献
11.
Summary The addition reaction of esters of nitroacetic acid to, -unsaturated ketones was studied, and new esters of ketonitroacids were prepared. 相似文献
12.
V. G. Nenaidenko S. V. Druzhinin E. S. Balenkova 《Russian Journal of Organic Chemistry》2008,44(4):485-488
β-Aryl-substituted α,β-unsaturated trifluoromethyl ketones react with ethyl cyanoacetate to give the corresponding Michael addition products, ethyl 3-aryl-2-cyano-6,6,6-trifluoro-5-oxohexanoates, which are formed as mixtures of two diastereoisomers. The reaction time and product yield depend on electron-donating properties of the substituent in the initial ketone. The reaction is not accompanied by intramolecular cyclization of the Michael adducts. 相似文献
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14.
《Tetrahedron: Asymmetry》2014,25(12):949-955
Chiral primary amine catalyzed direct asymmetric aldol reactions of ketones with trifluoroacetophenone, afforded trifluoromethylated β-hydroxycarbonyl aldol products bearing a quaternary carbon stereogenic center in high yields (up to 93% yield) and with high to excellent enantioselectivities of up to 99% ee. 相似文献
15.
Phosphonate reagents were developed for the two-carbon homologation of aldehydes or ketones to unbranched- or methyl-branched α,β-unsaturated aldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a protected aldehyde group instead of the usual ester group. A homologation cycle entailed condensation of the reagent with the starting aldehyde, followed by removal of the dimethylhydrazone protective group with a biphasic mixture of 1 M HCl and petroleum ether. This robust two-step process worked with a variety of aldehydes and ketones. Overall isolated yields of unsaturated aldehyde products ranged from 71% to 86% after the condensation and deprotection steps. 相似文献
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17.
Iridium phosphinitoxazoline complexes were found to be new efficient catalysts for the asymmetric hydrogenation of arylated α,β-unsaturated ketones. Linear as well as cyclic substrates are hydrogenated with similar success, giving selectivities of up to 99.7% ee. 相似文献
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19.
2-Fluoro-6-pyridinyloxy derivatives of 2-ethoxyvinyl carbinols react with radicals derived from xanthates by an addition-fragmentation pathway to give highly functionalized ketones after acid hydrolysis. 1,4-Diketones are readily accessible by this approach. α,β-Unsaturated ketones can be obtained by starting with geminal acetoxy xanthates prepared by addition of a simpler xanthate to vinyl acetate. 相似文献