Electrocyclic Additions Research Articles

Theoretical mechanistic study of the ethylene oxidation over permanganate: effect of BF3 Lewis acid

The mechanism of ethylene oxidation to ethylene glycol on the permanganate material has been investigated by density functional theory with the M06-L functionals. Effect of the BF3 coordination to the MnO4 − on the mechanism has been examined in details. The initial step is the activation of ethylene C=C bond via the [3+2] electrocyclic addition. The calculated reaction barrier of this step on MnO4 − material (53.67 kJ mol−1) is decreased significantly with the presence of BF3 (32.37 kJ mol−1). In the next step of cyclic intermediate hydration to ethylene glycol, the activation energies for the first and second hydrations are 136.14 and 93.03 kJ mol−1 on BF3–MnO4 −, and 147.08 and 134.87 kJ mol−1 on MnO4 −. These results demonstrate that the BF3 coordinated to the MnO4 − material can enhance the overall conversion of ethylene to ethylene glycol. Molecular orbital analysis provides more understanding regarding the role of BF3 in this reaction.

One or More CC Bond(s) Formed by Addition: Addition of Carbon Radicals and Electrocyclic Additions to CC Multiple Bonds

AbstractFor Abstract see ChemInform Abstract in Full Text.

ChemInform Abstract: One or More CC Bond(s) Formed by Addition: Addition of Carbon Radicals and Electrocyclic Additions to CC Multiple Bonds

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Substituent effects on 1,3-dipolar cycloadditions to some 1,1-diphenyl-2-aza-1,3-butadiene derivatives.

The reactivity and in particular the siteselectivity of [3+2] electrocyclic additions to 1,1-diphenyl-2-aza -1,3-butadienes, substituted or not on the terminal carbon with methyl and phenyl, and with a 3-carbomethoxyl group, have been investigated with the 1,3-dipolar reagents 4-nitrobenzonitrile oxide and diazomethane. The role of the 3-carbomethoxy substituent in determining the siteselectivity observed in these reactions is discussed in relation to experimental results and to conformational models of some of the tested 2-azadiene dipolarophiles calculated on AM1 bases.

Die kinetik der allendimerisation, ein beitrag zum mechanismus

The reaction kinetics of the dimerization of some polyhalogenated allenes with the general formula Cl 2 CCCCIX (X = Cl, Br, C 6 H 5 , COOEt) and of tetrabromoallene was studied by an IR spectrophotometric method. The reaction was found to be of strictly second order kinetics. The activation parameters were determined and the experimental data and the influence of the substituents were discussed in terms of the accepted general theory of allene cycloaddition. All data are in agreement with a non-concerted two-step electrocyclic addition mechanism. Within the experimental limits no paramagnetic species like a diradical could be detected by the ESR-method during the dimerization reaction of tetrachloroallene. Finally, an attempt was made to explain the extreme thermal instability of all polyhalogenated allenic monomers.

Kinetic control of stereochemistry in the addition of unsymmetrical ketens to cyclopentadiene

Assumption of an initial crosswise approach of cyclopentadiene and a keten, combined with simple frontier orbital considerations, leads to a prediction of stereochemistry in the electrocyclic addition which has been confirmed by experiment.

Electrocyclic addition of a cyclohexadienylic anion to a diene. Route to polycyclic compounds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrocyclic addition of a cyclohexadienylic anion to a diene. Route to polycyclic compoundsCharles Cottrell, Ralph C. Dougherty, Gideon Fraenkel, and Englebert PeccholdCite this: J. Am. Chem. Soc. 1969, 91, 26, 7545–7547Publication Date (Print):December 1, 1969Publication History Published online1 May 2002Published inissue 1 December 1969https://doi.org/10.1021/ja01054a075RIGHTS & PERMISSIONSArticle Views45Altmetric-Citations8LEARN 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 (362 KB) Get e-Alerts Get e-Alerts

Electrocyclic additions to pentacyclo[4.4.02,5.03,8.04,7]deca-9-ene

Electrocyclic additions to pentacyclo[4.4.02,5.03,8.04,7]deca-9-ene

Intramolecular electrocyclic reactions. Part I. Structure of ‘bromohydroxyphorone’: 3-bromo-5-hydroxy-4,4,5,5-tetramethylcyclopent-2-enone

αα′-Dibromophorone (3,5-dibromo-2,6-dimethylhepta-2,5-dien-4-one) as the conjugate acid undergoes intramolecular electrocyclic addition to give 3-bromo-5-hydroxy-4,4,5,5-tetramethylcyclopent-2-enone. The reactions of this substance, its bromine-free analogue and their derivatives, recorded by Ingold and Shoppee in 1928, are clarified and reinterpreted.