- Bromination of ketones with the systems H2O2-LiBr- CeIII and H2O2-LiBr-CeIV
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A new method for the synthesis of α-bromoketones was suggested. The C5-C11 linear and branched ketones in the reaction with the systems H2O2-LiBr-CeIII and H 2O2-LiBr-CeIV in acetonitrile were brominated at α-position. The reaction is highly selective.
- Nikishin,Sokova,Kapustina
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- A H2O2/HBr system-several directions but one choice: oxidation-bromination of secondary alcohols into mono- or dibromo ketones
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In this work we found that a H2O2-HBr(aq) system allows synthesis of α-monobromo ketones and α,α′-dibromo ketones from aliphatic and secondary benzylic alcohols with yields up to 91%. It is possible to selectively direct the process toward the formation of mono- or dibromo ketones by varying the amount of hydrogen peroxide and hydrobromic acid. The convenience of application, simple equipment, multifaceted reactivity, and compliance with green chemistry principles make the application of the H2O2-HBr(aq) system very attractive in laboratories and industry. The proposed oxidation-bromination process is selective in spite of known properties of ketones to be oxidized by the Baeyer-Villiger reaction or peroxidated with the formation of compounds with the O-O moiety in the presence of hydrogen peroxide and Bronsted acids.
- Nikishin, Gennady I.,Kapustina, Nadezhda I.,Sokova, Liubov L.,Bityukov, Oleg V.,Terent'ev, Alexander O.
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p. 28632 - 28636
(2018/08/31)
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- A Highly Efficient Method for the Bromination of Alkenes, Alkynes and Ketones Using Dimethyl Sulfoxide and Oxalyl Bromide
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The pairing of DMSO and oxalyl bromide is reported as a highly efficient brominating reagent for various alkenes, alkynes and ketones. This bromination approach demonstrates remarkable advantages, such as mild conditions, low cost, short reaction times, provides excellent yields in most cases and represents a very attractive alternative for the preparation of dibromides and α-bromoketones.
- Ding, Rui,Li, Jiaqi,Jiao, Wenyi,Han, Mengru,Liu, Yongguo,Tian, Hongyu,Sun, Baoguo
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p. 4325 - 4335
(2018/11/21)
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- New methodology for the synthesis of tetrahydrofuro[3,2-b]furan-2(3H)-one derivatives, synthons of natural products with biological interest
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A new methodology is presented to synthesize in a regio and stereoselective manner tetrahydrofuro[3,2-b]furan-2(3H)-one, structural subunit present in a wide variety of natural products present in plant, fungi, algae, insects, and other living organisms.
- Monta?a, ángel M.,Barcia, Joan A.,Grima, Pedro M.,Kociok-K?hn, Gabriele
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p. 6794 - 6806
(2016/10/04)
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- Oxidation of secondary alkanols with the system cerium ammonium nitrate-lithium bromide into ketones, α-bromo ketones, and α,α -dibromo ketones
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Oxidation of secondary alkanols with the system Ce(NH4) 2(NO3)6-LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol : CeIV : LiBr).
- Nikishin,Sokova,Kapustina
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experimental part
p. 391 - 395
(2011/02/17)
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- Oxidation of primary and secondary alkanols with the CeIII-LiBr- H2O2 system
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Action of a novel oxidation system, Ce(NO3)3? 6H2O (cat.)-LiBr (cat.)-H2O2 (stoichiometric oxidant) on primary aliphatic C6-C9 alcohols gives selectively esters, whereas secondary aliphatic C5-C9 alcohols are converted into ketones. Selectivity of these transformations is provided by slow addition of H2O2 to the other reactants.
- Kapustina,Sokova,Nikishin
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experimental part
p. 1284 - 1288
(2011/02/23)
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- NOUVELLES METHODES DE DESHALOGENATION ET DE FORMATION D'ETHERS D'ENOL TRIMETHYLSILYLIQUES PAR ACTION DE iPr2NLi SUR QUELQUES α-MONOBROMO- ET α,α'-DIBROMOCETONES
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Attempts to prepare 2-bromo-2,4-dimethyl,3-trimethylsiloxy 3-pentene reacting lithium diisopropylamide (LDA) with 2-bromo-2,4-dimethyl-3 pentanone have revealed two new reactions.After a few minutes quantitative yields are obtained of either the dehalogenated ketone (after hydrolysis) or the trimethylsilyl enol ether (after addition of trimethylsilyl chloride).These reactions are general and have been extended to other α-monobromoketones and α,α'-dibromoketones.In the latter case, the reaction is more complex and leads generally to dehalogenation or reduction products.
- Lion, Claude,Dubois, Jacques-Emile,Lebbar, Khadija
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p. 119 - 126
(2007/10/02)
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- Synthese de quelques structures encombrees derivees de l'adamantane et de ses analogues par alkylation des ether d'enol trimethylsilyliques
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Alkylation of trimethylsilyl enol ethers of 2,4-dimethyl-3-pentanone, cyclopentanone and cyclohexanone has been extended to alkylating agents with a cage structure (substituted or functionalized adamantyl, diamantyl, homoadamantyl and noradamantyl chlorides or bromides).This method affords some new cage structured aliphatic and alicyclic ketones.In some cases one observes a new TiCl4 promoted reaction where the bromine in the alkylating agent is replaced by chlorine.This work is a generalization of our previous extended studies on α-alkylation of ketones with tertiary alkylating agents.
- Dubois, Jacques-Emile,Lebbar, Kadija,Lion, Claude,Dugast, Jean-Yves
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p. 905 - 910
(2007/10/02)
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