Electrochemical and spectroscopic behavior of trifluoromethylacetophenone in aqueous and micellar medium

Abstract

The electrochemical behavior of 4-trifluoromethylacetophenone (TFMA) has been studied in aqueous (2 ≤ pH ≤ 10), micellar, and ethanolic solutions using polarographic techniques. A slow hydration process of the carbonyl group has been observed by means of polarography and UV–visible spectrophotometry. Besides the well-known pH dependence of the electroreduction of aromatic ketones, C—F bond cleavages concomitant to the ketone reduction occur under electrolysis conditions in alkaline medium (pH = 10) at a very negative potential (−1.7 V), leading to the formation of 4-methylacetophenone, which is reduced at this potential with formation of the carbinol and of symmetrical and dissymmetrical pinacols. Finally, the reduction of TFMA has been performed in the presence of chiral surfactants in order to test their ability to induce an asymmetric induction. Keywords: 4-trifluoromethylacetophenone, 4-methylacetophenone, electroreduction, micellar medium, chiral surfactants, hydration, C—F bond fission.