Oxidation Of Alkynes Research Articles

The Preparation ofalpha-Diones. Phase-Transfer Assisted Oxidation of Alkynes by Potassium Permanganate

The Preparation of<i>alpha</i>-Diones. Phase-Transfer Assisted Oxidation of Alkynes by Potassium Permanganate

A comparative study of the direct anodic oxidation of olefins and acetylenes in non aqueous solvents

The results of electrode kinetic, preparative and theoretical studies of the direct anodic oxidation of related olefins and acetylenes are compared (phenylacetylene/styrene; vinylacetylene/butadiene; 1,4-diphenylbutadiene/1,4-diphenylbutadiyne). Modified HMO-calculation (β-modification according to bond lengths) predict the observed difference of the half wave potentials of related olefins and acetylenes qualitatively. However the HMO-calculations do not allow the precise prediction of the reactivities of anodically formed radical cations of the acetylenes except for the highly conjugated diphenylbutadiyne. Electrode kinetic and preparative data of the olefin and acetylene oxidation show that both react in the same way ie, are oxidized in the adsorbed state to yield monomeric and dimeric products. The remarkably low dimer yield in the acetylene oxidation is supposed to be due to the decreased adsorbability of the acetylenes at the higher anode potentials which are necessary to oxidize them. This phenomenon is observed, too, if olefins with different half wave potentials are compared.

The direct anodic oxidation of acetylenes in non-aqueous solvents

The direct anodic oxidation of acetylenes in non-aqueous solvents

The direct anodic oxidation of acetylenes in non-aqueous solvents

The direct anodic oxidation of acetylenes in non-aqueous solvents

Sulphines. Part VIII. Kinetics and mechanism of the reaction between aryl sulphines and perbenzoic acid

Aryl sulphines are converted by perbenzoic acid into benzophenones, sulphur, and sulphur dioxide. The reaction shows kinetic features, namely the rate law as well as substituent and solvent effects, similar to those reported for the oxidation of thiones, sulphides, alkenes, acetylenes, and diazoalkanes with the same peroxyacid. The reaction is an example of oxidation of a cumulative, double-bond system and a multi-step reaction mechanism is advanced. The rate-limiting step is electrophilic attack of the peracid on the carbon–sulphur double bond of the CSO group to form a cyclic sulphinic ester; this intermediate, by rapid cleavage, gives the ketone and sulphur monoxide, the latter disproportionating into sulphur and sulphur dioxide. The reaction rates of the E- and Z-isomers of mesityl phenyl sulphine compared with that for diphenyl sulphine, give further evidence for the proposed mechanism.

Metal-catalysed oxidation of acetylenes and diazo-ketones

The molybdenum-catalysed oxidation of acetylenes and the metal-catalysed decompositions and oxidations of α-diazo-ketones appear to proceed via transient metal–oxocarbene complexes. The formation of oxirens as intermediates in these reactions is excluded. The initial product from these oxidations is the corresponding α-diketone.

Thallium in organic synthesis. XXVIII. Selective oxidation of acetylenes to carboxylic acids, acyloins, benzils, and arylacetic acids with thallium(III) nitrate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThallium in organic synthesis. XXVIII. Selective oxidation of acetylenes to carboxylic acids, acyloins, benzils, and arylacetic acids with thallium(III) nitrateAlexander McKillop, Otto H. Oldenziel, Brian P. Swann, Edward C. Taylor, and Roger L. RobeyCite this: J. Am. Chem. Soc. 1971, 93, 26, 7331–7333Publication Date (Print):December 1, 1971Publication History Published online1 May 2002Published inissue 1 December 1971https://doi.org/10.1021/ja00755a044RIGHTS & PERMISSIONSArticle Views81Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (327 KB) Get e-Alerts Get e-Alerts

N-Bromosuccinimide-Induced Dimethyl Sulfoxide Oxidation of Acetylenes

The addition of less than 2 mol equiv. of N-bromosuccinimide (NBS) to a solution of diphenylacetylene in anhydrous dimethylsulfoxide (DMSO) leads to the formation of benzil in near-quantitative yield at room temperature. Under the same conditions stilbene gives the dibromo adduct. The conditions for this novel oxidation of an acetylene have been examined in some detail and it has been established that anhydrous DMSO must be employed as the solvent and that NBS is uniquely able to induce the oxidation. Preliminary studies indicate that alkyl aryl, dialkyl, and terminal acetylenes are converted to the corresponding α-dicarbonyl compounds, and that diphenylbutadiyne is oxidized to diphenyltetraketone. Optimum conditions for these latter oxidations have not yet been established.

Preparation of conjugated acetylenic ketones by oxidation of alkynes with chromium trioxide-pyridine complex or sodium chromate

Preparation of conjugated acetylenic ketones by oxidation of alkynes with chromium trioxide-pyridine complex or sodium chromate

Ruthenium tetroxide oxidation of alkynes. A new one step synthesis of α-diketones

Ruthenium tetroxide oxidation of alkynes. A new one step synthesis of α-diketones

Peracid oxidation of acetylenes. 1,2-Methyl migration, cyclopropane formation, and stereoselective 1,5- and 1,6-transannular insertion

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPeracid oxidation of acetylenes. 1,2-Methyl migration, cyclopropane formation, and stereoselective 1,5- and 1,6-transannular insertionJoseph Ciabattoni, R. A. Campbell, C. A. Renner, and P. W. ConcannonCite this: J. Am. Chem. Soc. 1970, 92, 12, 3826–3828Publication Date (Print):June 1, 1970Publication History Published online1 May 2002Published inissue 1 June 1970https://doi.org/10.1021/ja00715a068RIGHTS & PERMISSIONSArticle Views307Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (404 KB) Get e-Alerts Get e-Alerts

Alkyne oxidation III. Competitive features and degenerate branching

A comparison is made between the slow com bustions of propyne and butyne-2 which are degenerately branched and acetylene which is not. The relative rates of ‘oxidation’ radical attack on these alkynes and a number of the reactive intermediates formed in their slow combustions have been obtained from their separate and competitive oxidations. The results confirm that the same electrophilic radical species (hydroxyl or hydroperoxyl) is involved in the oxidations of acetylene, propyne and butyne-2. It is concluded that the branching intermediate is a peracid formed from an aldehyde in the case of propyne and an acyl radical in butyne-2 oxidation, which produces only traces of aldehydes, by the sequence: RCHO + X˙→ RĊO + HX ; RĊO + O 2 → RCO˙ 3 ; RCO˙ 3 + RʹH→ RCO 3 H + Rʹ˙ ; RCO 3 H → R˙ + CO 2 +˙OH, where X˙ is a chain carrier and RʹH a molecule with a labile hydrogen atom. In acetylene oxidation the hydrogen abstraction reaction is too slow to compete with alternative reactions of the acyl radical and hence it is not branched.