Condensation of beta-diester titanium enolates with carbonyl substrates: a combined DFT and experimental investigation.
Fiche publication
Date publication
novembre 2009
Auteurs
Membres identifiés du Cancéropôle Est :
Pr SAPI Janos, Dr GERARD Stéphane
Tous les auteurs :
Marrone A, Renzetti A, De Maria P, Gerard S, Sapi J, Fontana A, Re N
Lien Pubmed
Résumé
The condensation of dialkyl beta-diesters with various aldehydes promoted by TiCl4 has been studied by DFT approaches and experimental methods, including NMR, IR and UV/Vis spectroscopy. Various possible reaction pathways have been investigated and their energy profiles evaluated to find out a plausible mechanism of the reaction. Theoretical results and experimental evidence point to a three-step mechanism: 1) Ti-induced formation of the enolate ion; 2) aldol reaction between the enolate ion and the aldehyde, both coordinated to titanium; and 3) intramolecular elimination that leads to a titanyl complex. The presented mechanistic hypothesis allows one to better understand the pivotal role of titanium(IV) in the reaction.
Référence
Chemistry. 2009 Nov 2;15(43):11537-50.