Predicting the reaction mechanism of nucleophilic substitutions at carbonyl and thiocarbonyl centres of esters and thioesters

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dc.contributor.authorOrmazábal-Toledo, Rodrigo
dc.contributor.authorCastro, Enrique
dc.contributor.authorSantos, Jose
dc.contributor.authorMillan, Daniela
dc.contributor.authorCañete, Alvaro
dc.contributor.authorContreras, Renato
dc.contributor.authorCampodónico, Paola
dc.date.accessioned2017-05-25T15:31:23Z
dc.date.available2017-05-25T15:31:23Z
dc.date.issued2012
dc.descriptionCentro de Química Médica
dc.description.abstractIn nucleophilic substitution reactions at carbonyl centres, there are two possible channels. The first one occurs when the attack of nucleophilic agents takes place simultaneously with the departure of the nucleofuge. This process is named as concerted. The second possibility is the formation of a reaction intermediate, typically a tetrahedral intermediate from which the nucleofuge departs after passing through a second transition state. This second mechanism is defined as stepwise. Whether a concerted or stepwise mechanism is to be expected for a given reaction depends on several factors. Among these determinants are the nucleophilicity of the attacking group, the leaving group ability of the nucleofuge, and the solvent, which affects both the stability of the intermediate or the transition states involved. The role of the electrophilic centre can however become an important factor that can determine the reaction mechanism. In this work we show that the group nucleophilic Fukui function model may be used to rationalize and to predict the reaction mechanism of the title compounds towards alicyclic amines. In general, when the electrophilic carbon centre is attached to the soft sulfur atom, the reaction mechanism is predicted to follow a stepwise route. When the electrophilic carbon atom is attached to a harder oxygen centre, the reaction mechanism is determined by chemical substitution at the nucleofuge moiety. Experimental verification for a set of four substrates is presented.
dc.format.extent6
dc.identifier.citationJOURNAL OF PHYSICAL ORGANIC CHEMISTRY Volume 25, Issue 12 December 2012 Pages 1359–1364
dc.identifier.urihttp://hdl.handle.net/11447/1330
dc.identifier.urihttp://dx.doi.org/10.1002/poc.3048
dc.language.isoen_US
dc.publisherJohn Wiley & Sons
dc.subjectreaction mechanisms
dc.subjectkinetic measurements
dc.subjectgroup Fukui function
dc.subjectelectron density reorganization
dc.subjectcarbonyl derivatives
dc.titlePredicting the reaction mechanism of nucleophilic substitutions at carbonyl and thiocarbonyl centres of esters and thioesters
dc.typeArtículo

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