- Salt effects on the reactivity and the stability of organomanganese reagents
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The reactivity and the stability of organomanganese reagents prepared from the ate complexes MnX2·2LiBr (X= Br,I) and MnCl2·R4NX (X= Br, Cl) were studied. The preparation and the use for synthetic applications of stable sec- and tert-alkylmanganese bromides in ether as well as the acylation of RMnCl by R'COOCOOEt in THF were successfully achieved for the first time.
- Cahiez, Gerard,Razafintsalama, Lynah,Laboue, Blandine,Chau, Francois
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p. 849 - 852
(2007/10/03)
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- Organomanganese (II) reagents XXIII: Manganese-catalyzed acylation of organomagnesium compounds by car·ylic acid chlorides
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In the presence of a catalytic amount of manganese chloride (3% MnCl4Li2), organomagnesium reagents react with car·ylic chlorides, in THF between 0 and 10°C, to give the corresponding ketones in high yields. The scope of the reaction is very large; alkyl, alkenyl and aryl magnesium reagents have been used successfully. The selectivity of the reaction allows to prepare various fonctionalized ketones from car·ylic acid chlorides bearing a functional group (Cl, Br, ester nitrile and even a ketone).
- Cahiez, Gerard
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p. 4439 - 4442
(2007/10/02)
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- ORGANOMANGANESE (II) REAGENTS XIX. ACYLATION OF ORGANOMANGANESE CHLORIDES BY CARBOXYLIC ACID CHLORIDES IN THF: A CLEAR IMPROVEMENT IN THE FIELD OF THE PREPARATION OF KETONES FROM ORGANOMANGANESE COMPOUNDS.
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Organomanganese chloride reagents react with carboxylic acid chlorides, in THF, to give the corresponding ketones in excellent yields.The reaction is of broad scope, it is very interesting from practical and economical point of view since organomanganese chlorides (in THF) are the most stable and cheap organomanganese reagents.With methyl, aryl, alkenyl and s- or t-alkylmanganese chlorides, the acylation is advantageously performed in the presence of a catalytic amount of copper chloride.This new procedure allows to prepare methyl, aryl and alkenylketones as well as s- or t-alkylketones in good yields.
- Cahiez, Gerard,Laboue, Blandine
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p. 7369 - 7372
(2007/10/02)
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- A SIMPLE WAY TO SOME KETONE HOMOENOLATES
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Under basic conditions 1-alkene-3-ols were converted into ketone homoenolates which led to β-alkylated ketones.
- Cuvigny, Therese,Julia, Marc,Jullien, Ludovic,Rolando, Christian
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p. 2587 - 2590
(2007/10/02)
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- AZO ANIONS IN SYNTHESIS. PT 1. t-BUTYLHYDRAZONES AS ACYL-ANION EQUIVALENTS
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The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides, crotonates) to form C-trapped t-butylazo-compounds; tautomerisation and hydrolysis gave α-hydroxy ketones, ketones, and γ-keto esters in good yield, thereby providing a convenient new acyl-anion equivalent.Reaction of these lithium salts with aldehydes and ketones, followed by elimination provided a new route to azo alkenes.
- Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Kolhe, Jayant N.,Perry, Matthew W. D.,Jain, Ashok U.
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p. 4223 - 4234
(2007/10/02)
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- A HIGHLY EFFICIENT SYNTHETIC ROUTE TO KETONES THROUGH SEQUENTIAL COUPLING REACTIONS OF GRIGNARD REAGENTS WITH S-PHENYL CARBONOCHLORODITHIOATE IN THE PRESENCE OF NICKEL OR IRON CATALYSTS
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The sequential coupling reactions of Grignard reagents with S-phenyl carbonochloridothioate in the presence of nickel(II) or iron(III) catalysts provides a very mild and straightforward route to symmetrical and unsymmetrical aliphatic and aromatic ketones.
- Cardellicchio, C.,Fiandanese, V.,Marchese, G.,Ronzini, L.
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p. 3595 - 3598
(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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- Azo Anions in Synthesis. t-Butylhydrazones as Acyl-anion Equivalents
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The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides) to form C-trapped t-butylazo compounds; isomerisation and hydrolyse gave α-hydroxy ketones and ketones in good yields, thereby providing a convenient new acyl-anion equivalent.
- Adlington, Robert M.,Baldwin, Jack E.,Bottaro, Jeffrey C.,Perry, Matthew W. D.
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p. 1040 - 1041
(2007/10/02)
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