- Catalytic ketonisation over oxide catalysts. Part IX. Single step synthesis of aliphatic saturated and unsaturated C11 - C 13 ketones from carboxylic acids
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Metameric undecan-x-ones (x = 2-6), dodecan-y-ones (y = 2-5), tridecan-z-ones (z = 4-7) and two unsaturated aliphatic ketones were prepared by vapor phase ketonisation of the appropriate monocarboxylic acids in the presence of 20 wt% MnO2/Al2O3 catalyst under flow conditions. The ketones were obtained in yields between 48 and 89% in a multigram scale (80-250 g). Their physical and spectral data have been determined.
- Glinski,Gibka
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p. 299 - 302
(2007/10/03)
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- One-pot dialkylation of allylphenylsulfide induced by aminoalkoxides- activated NaNH2. Application to the synthesis of unsymmetrical ketones
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It is shown that the activation of NaNH2 by sodium aminoalkoxides, leading to new superbases, induced an efficient one-pot dialkylation of allylphenylsulfide. The regioselectivity of the reaction (α,α' vs α,γ) was found as strongly dependent on the nature of the alkyl halide. As an application, α,γ dialkylated products were efficiently converted Into the corresponding unsymmetrical ketones.
- Choppin, Sabine,Gros, Philippe,Fort, Yves
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p. 9261 - 9268
(2007/10/03)
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- CuBr2-LiOBut as a New Reagent for Oxidation of Alcohols
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The reagent of the title was found to promote the oxidation of alcohols to give the corresponding carbonyl compounds in good yields.The copper(II) oxidizing agent was easily prepared by the reaction of copper(II) bromide with lithium t-butoxide in THF.
- Yamaguchi, Jun-ichi,Yamamoto, Shiori,Takeda, Takeshi
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p. 1185 - 1188
(2007/10/02)
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- STEREOCHEMICAL ASSIGMENT BY MASS SPECTROMETRY. DOUBLE BOND GEOMETRICAL ISOMERS OF 3,5-DIALKYLCYCLOHEXYLIDENE ACETIC ACID ESTERS AND 3-ALKYL-2-ALKENOATES
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Mass spectrometry is best physical method for the configurational assignment of E- and Z-3,5-dialkylcyclohexylidene acetic acid esters 1 and E- and Z-3-alkyl-2-alkenoates 2.The homoallylic cleavage resulting in the loss of the C-3 and C-5 alkyl groups from 1 and of the two δ-alkyls from 2 is a stereospecific process: the loss of the group which is adjacent to the carbonyl is significantly preferred.The stereospecifity of this fragmentation is interpreted in terms of a hidden hydrogen transfer preceding the carbon-carbon bond cleavage.
- Merksammer, Israel,Mandelbaum, Asher
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p. 775 - 780
(2007/10/02)
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- REACTIVITE DES DERIVES ORGANOMANGANEUX-VIII; PREPARATION DE CETONES PAR ACYLATION D'ORGANOMANGANEUX. INFLUENCE DE LA NATURE DE L'AGENT ACYLANT, DES SOLVANTS ET DES LIGANDS
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The influence of the nature of acylating reagents, solvents and ligands on the preparation of ketones by acylation of organomanganous reagents is studied.Thus acid chlorides in ether, symmetrical acid anhydrides in ether or THF and mixed carboxylic-carbonic anhydrides (R'COOCOOEt) in ether are compared, they lead to the corresponding ketones with good or excellent yields.Some problems of reproductibility are encountered and discussed when mixed anhydrides R'COOCOOEt are used in THF.The addition of a great variety of cosolvents (e.g.C6H6, AcOEt, CO3Et2, CH3CN, CH2Cl2...) to the reaction mixture before addition of the acylating reagent does not affect the yield of ketones.In comparison the complexation of organomanganous reagents by several ligands (e.g.Me2S or Ph3P) has no subsequent effect on their acylation.The main limitation for the choice of solvents or ligands is the use of amino derivatives which generally lead to a very low yield of ketones (e.g.C5H5N, TMEDA, Et3N) or unreproducible yields (e.g.HMPA).Two applications of these studies are described: -The stabilization of s or t-alkyl manganous derivatives by complexation which leads to the best yield of the corresponding ketones -The use of a cosolvent in order to increase the yield when mixed anhydrides R'COOCOOEt are used in THF.
- Friour, G.,Alexakis, A.,Cahiez, G.,Normant, J.
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p. 683 - 694
(2007/10/02)
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- A General Synthesis of Ketones from Alkenes via Stepwise Hydroboration with Thexylchloroborane
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Thexylalkylchloroboranes, reduced in the presence of a second alkene, produced mixed thexyldialkylboranes in high purity.These derivatives are readily transformed into the corresponding ketones by carbonylation or cyanidation, providing for the first time a general conversion of two different olefins into the corresponding ketone.
- Kulkarni, Surendra U.,Lee, Hsiupu D.,Brown, Herbert C.
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p. 4542 - 4543
(2007/10/02)
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