(Invited) Electrochemical Multi-Electron Oxidation of Thiophene-Derivatives Promoted by Coordination of Electrolytes

Abstract

Supporting electrolyte is an essential component of the electrochemical systems, although its effect on the reactivity of electrochemically generated cation/anion species has been rarely discussed.[1][2] Our recent study on the electrochemical behavior of tellurium-containing π-conjugated molecule revealed that the coordination of anion species toward the electrochemically generated radical cation species determines the number of electrons, where 1e/2e oxidation were switched depending on the donor number of electrolyte-derived anion species as well as solvents.[3] In the present study, we expanded this idea to thiophene-derivatives to explore the synthetic applicability of electrolyte-coordination. As expected, electrolyte-dependent oxidation behavior of π-expanded thiophene derivatives was confirmed. Especially, the use of coordinating anion promoted multi-electron oxidation of thiophene derivatives, which enabled facile C-C coupling chemistry and oxidative intramolecular cyclization to give rare thiophenium motif in a single step. This study implies the importance of a rational design of the electrolyte to develop novel electrosynthetic reactions.[1] N. Shida, Electrochemistry, 2022, 90, 101004[2] S. Yoshinaga, M. Atobe, N. Shida, Electrochemistry, in press (DOI: 10.5796/electrochemistry.23-67013)[3] N. Shida, H. Nishiyama, F. Zheng, S. Ye, D. S. Seferos, I. Tomita, S. Inagi, Commun. Chem. 2019, 2, 124. Figure 1