Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/60940
Type: Artigo de periódico
Title: Ketalization of gaseous acylium ions
Author: Moraes, LAB
Eberlin, MN
Abstract: A novel reaction of gaseous acylium ions: ketalization with diols and analogs, has been systematically studied via pentaquadrupole MS2 and MS3 experiments and ab initio calculations. A variety of alpha,beta -diols and their amino, thiol, ether, and thioether analogs have been tested for reactivity, mechanism evaluation, site selectivity, and for the effects of alpha- and beta -interfunctional separation. As for condensed-phase ketalization of neutral carbonyl compounds followed by hydrolysis, gaseous acylium ions are chemically deactivated in the form of cyclic ionic ketals by ketalization, and are efficiently released via on-line collision-induced dissociation. Ketalization of acylium ions is shown to identify and structurally characterize alpha,beta -diols and their analogs, and to distinguish regioisomers. Diastereomers can also be distinguished, as illustrated for cis and trans 1,2-diaminocyclohexane. The MS2 and MS3 data together with O-18-labeling and ab initio calculations establish for acylium ion ketalization a mechanism of anchimeric assistance with participation of the neighboring acyl group. (C) 2001 American Society for Mass Spectrometry.
Country: EUA
Editor: Elsevier Science Inc
Rights: fechado
Identifier DOI: 10.1016/S1044-0305(00)00211-7
Date Issue: 2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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