Synthesis of Flavones through NaI‐Mediated Electrochemical Cyclization of Chalcones

Abstract

A mild electrochemical oxidative cyclization for the synthesis of flavones from easy‐access 2’‐hydroxychalcones was developed using an inexpensive NaI as mediator and electrolyte under ambient temperature in a mixture of EtOH and H2O as solvent. This method was successfully applied to synthesize 26 examples of flavones from a variety of functionalized 2’‐hydroxychalcones. A gram‐scale formal synthesis of bioactive scutellarein was successfully demonstrated. The main advantages of this reaction include its broad substrate scope, scalability, ability to operate with benign solvent, and no requirement for strong oxidizing agents and external additives.

NaI-Mediated Electrochemical Cyclization–Desulfurization for the Synthesis of N-Substituted 2-Aminobenzimidazoles

“…Therefore, numerous synthetic methods have been developed using iodide-mediated C–N bond formation under electrochemical processes to prepare various N -heterocycle compounds, including isatins, , oxadiazoles, aziridines, , arizines, quinazolinones, , indoles, , indolines, − etc . Lately, our group has successfully developed the synthesis of various compounds, including amides, 2-aminobenzoxazoles, chalcone, and guanidines, using the iodide-mediated electrochemical approach. Continuing our research in this area, we aim to expand this method to synthesize N -substituted 2-aminobenzimidazoles 3 through an addition–desulfurization process between N -substituted o -phenylenediamines 1 and isothiocyanates 2 (Scheme b).…”