Mono and double polar [4+2(+)] Diels-Alder cycloaddition of acylium ions with O-heterodienes

dc.creatorMeurer, EC
dc.creatorEberlin, MN
dc.date2002
dc.dateFEB
dc.date2014-11-17T06:21:20Z
dc.date2015-11-26T16:57:49Z
dc.date2014-11-17T06:21:20Z
dc.date2015-11-26T16:57:49Z
dc.date.accessioned2018-03-28T23:45:26Z
dc.date.available2018-03-28T23:45:26Z
dc.identifierJournal Of Mass Spectrometry. John Wiley & Sons Ltd, v. 37, n. 2, n. 146, n. 154, 2002.
dc.identifier1076-5174
dc.identifierWOS:000173964300002
dc.identifier10.1002/jms.267
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/57859
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/57859
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/57859
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1277773
dc.descriptionGas-phase reactions of acylium ions with alpha, beta-unsaturated carbonyl compounds were investigated using pentaquadrupole multiple-stage mass spectrometry. With acrolein and metacrolein, CH3-C+=O, CH2=CH-C+=O, C6H5-C+=O, and (CH3)(2)N-C+=O react to variable extents by mono and double polar [4+2(+)] Diels-Alder cycloaddition. With ethyl vinyl ketone, CH3-C+=O reacts exclusively by proton transfer and C6H5-C+=O forms only the mono cycloadduct whereas CH2=CH-C+=O and (CH3)(2)N-C+=O reacts to great extents by mono and double cycloaddition. The positively charged acylium ions are activated O-heterodienophiles, and mono cycloaddition occurs readily across their C+=O bonds to form resonance-stabilized 1,3-dioxinylium ions which, upon collisional activation, dissociate predominantly by retro-addition. The mono cycloadducts are also dienophiles activated by resonance-stabilized and chemically inert 1,3-dioxonium ion groups, hence they undergo a second cycloaddition across their polarized C=C ring double bonds. O-18 labeling and characteristic dissociations displayed by the double cycloadducts indicate the site and regioselectivity of double cycloaddition, which are corroborated by Becke3LYP/6-311++G(d,p) calculations. Most double cycloadducts dissociate by the loss of a RCO2COR1 molecule and by a pathway that reforms the acylium ion directly. The double cycloadduct of the thioacylium ion (CH3)(2)N-C+=S with acrolein dissociates to (CH3)(2)N-C+=O in a sulfur-by-oxygen replacement process intermediated by the cyclic monoadduct. The double cycloaddition can be viewed as a charge-remote type of polar [4+2(+)] Diels-Alder cycloaddition reaction. Copyright (C) 2001 John Wiley Sons, Ltd.
dc.description37
dc.description2
dc.description146
dc.description154
dc.languageen
dc.publisherJohn Wiley & Sons Ltd
dc.publisherW Sussex
dc.publisherInglaterra
dc.relationJournal Of Mass Spectrometry
dc.relationJ. Mass Spectrom.
dc.rightsfechado
dc.rightshttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dc.sourceWeb of Science
dc.subjectacylium ions
dc.subjectalpha,beta-unsaturated carbonyl compounds
dc.subjectO-heterodienes
dc.subjection-molecule reactions
dc.subjectpentaquadrupole tandem mass spectrometry
dc.subjectpolar [4+2(+)] Diels-Alder cycloaddition reactions
dc.subjectPentaquadrupole Mass-spectrometer
dc.subject1,3-butadiene Radical-cation
dc.subjectGas-phase
dc.subjectMolecule Reactions
dc.subjectCyclotron-resonance
dc.subjectCarbonyl-compounds
dc.subjectTrap
dc.subjectReactivity
dc.subjectChemistry
dc.subjectTransacetalization
dc.titleMono and double polar [4+2(+)] Diels-Alder cycloaddition of acylium ions with O-heterodienes
dc.typeArtículos de revistas


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