Premium
Condensation of β‐Diester Titanium Enolates with Carbonyl Substrates: A Combined DFT and Experimental Investigation
Author(s) -
Marrone Alessandro,
Renzetti Andrea,
De Maria Paolo,
Gérard Stéphane,
Sapi Janos,
Fontana Antonella,
Re Nazzareno
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901595
Subject(s) - aldol condensation , titanium , aldehyde , condensation , chemistry , reaction mechanism , intramolecular force , condensation reaction , ion , computational chemistry , mechanism (biology) , photochemistry , aldol reaction , spectroscopy , inorganic chemistry , organic chemistry , catalysis , thermodynamics , philosophy , physics , epistemology , quantum mechanics
The condensation of dialkyl β‐diesters with various aldehydes promoted by TiCl 4 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.