Aromatization of cyclohexadienes by TEMPO electro-mediated oxidation: Kinetic and structural aspects

• Published in: Electrochemistry communications Vol. 7; no. 12; pp. 1445 - 1448
• Main Authors: Breton, Tony, Liaigre, Denis, Belgsir, El Mustapha
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-12-2005; Amsterdam Elsevier Science; New York, NY Elsevier
• Subjects: Aromatization; Chemical Sciences; Chemistry; Cyclohexadienes; Electrochemistry; Electrosynthesis; Exact sciences and technology; General and physical chemistry; Kinetics and mechanism of reactions; or physical chemistry; Oxidation; TEMPO; Theoretical and; Cyclohexadienes; Electrosynthesis; Aromatization; Oxidation; TEMPO; Kinetic control; Catalytic reaction; Dienic compound; Experimental study; Cyclic voltammetry; Organic free radical; Homogeneous catalysis; Oxidative degradation; Electrochemical reaction; Monocyclic compound
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2005.09.029

Cyclohexadienes are easily converted into the corresponding aromatics in excellent yield (>90%) in the presence of 2,2,6,6-tetramethyl-1-oxopiperidinium ion (TEMPO
+). The TEMPO radical was used in catalytic amount and was electrochemically regenerated in the presence of 2,6-lutidine as a base in hydro-organic medium (AcCN/H
2O 95/5). This work has been focused on the kinetic aspects. We have demonstrated that the reactivity of different cyclohexadienes is strongly dependent on the configuration of the double bonds and on the nature of the substituents. Competition between allylic functionalization and aromatization has been observed during the oxidation of 1,2-dihydro-4-phenylnaphthalene.