2012 |
Ormazabal-Toledo, R; Castro, E A; Santos, J G; Millan, D; Canete, A; Contreras, R; Campodonico, P R Predicting the Reaction Mechanism of Nucleophilic Substitutions at Carbonyl and Thiocarbonyl Centres of Esters and Thioesters Artículo de revista Journal of Physical Organic Chemistry, 25 (12), pp. 1359-1364, 2012, ISSN: 0894-3230. Resumen | Enlaces | BibTeX | Etiquetas: aminolysis, carbonyl carboxylic center, contrasting density derivatives, dithiocarbonates, electron electrophilic esters, fukui function, group group, kinetic kinetics, leaving measurements, mechanisms, o-ethyl phenyl, reaction reactivity, reorganization, secondary @article{RN103, title = {Predicting the Reaction Mechanism of Nucleophilic Substitutions at Carbonyl and Thiocarbonyl Centres of Esters and Thioesters}, author = { R. Ormazabal-Toledo and E.A. Castro and J.G. Santos and D. Millan and A. Canete and R. Contreras and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000313125800038}, doi = {10.1002/poc.3048}, issn = {0894-3230}, year = {2012}, date = {2012-01-01}, journal = {Journal of Physical Organic Chemistry}, volume = {25}, number = {12}, pages = {1359-1364}, publisher = {2012 John Wiley & Sons, Ltd.}, abstract = {In 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.}, keywords = {aminolysis, carbonyl carboxylic center, contrasting density derivatives, dithiocarbonates, electron electrophilic esters, fukui function, group group, kinetic kinetics, leaving measurements, mechanisms, o-ethyl phenyl, reaction reactivity, reorganization, secondary}, pubstate = {published}, tppubtype = {article} } In 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. |
2012 |
Predicting the Reaction Mechanism of Nucleophilic Substitutions at Carbonyl and Thiocarbonyl Centres of Esters and Thioesters Artículo de revista Journal of Physical Organic Chemistry, 25 (12), pp. 1359-1364, 2012, ISSN: 0894-3230. |