Synthesis of Flavones through NaI‐Mediated Electrochemical Cyclization of Chalcones

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. Control experiments were conducted to disclose a possible indirect oxidation via in situ generation of iodine. 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.