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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/159605
On the mechanism of phenolic formylation mediated by TiCl4 complexes: existence of diradical intermediates induced by valence tautomerism
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The conventional electrophilic intramolecular aromatic substitution pathway proposed by Cresp et al. [J. Chem. Soc., Perkin Trans. 1 1973, 340 345] is confirmed by the observed products of phenolic formylation mediated by TiCl4. However, when the nucleophilic path is quenched by appropriate ligand modification, the initial equilibria between the possible neutral complexes of TiCl4 with 3,5-dimethoxy-phenol and/or diethyl ether lead to different stable diradical intermediates induced by valence tautomerism that provide valuable activated reagents. Some of these species have been detected by EPR, characterized theoretically and captured by TEMPO, thus providing a consistent mechanism for the reaction with one or more equivalents of TEMPO per phenol.
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HERAS, Carlos, et al. On the mechanism of phenolic formylation mediated by TiCl4 complexes: existence of diradical intermediates induced by valence tautomerism. European Journal of Organic Chemistry. 2015. Vol. 2015, num. 10, pags. 2111-2118. ISSN 1434-193X. [consulted: 13 of June of 2026]. Available at: https://hdl.handle.net/2445/159605