Electrochemical Synthesis of Sulfonyl Fluorides with Triethylamine Hydrofluoride

Comprehensive Summary Hydrofluoride is an industry‐preferred fluoride source, and finds extensively application to manufacture diverse fluoro chemicals. The Et3N‐3HF complex is a liquid HF with improve safety. In this work, we report electrochemical synthesis of a series of sulfonyl fluoride with Et3N‐3HF as fluoride source. The sulfinic salt is a smell‐less, non‐volatile, and air‐stable sulfur source in this reaction. With the combination of Et3N‐3HF and aryl/alkyl sulfinic salt, the sulfonyl fluorides are achieved without the use of external oxidant. In addition, we demonstrate further advantage in a tandem reaction involving Pd‐catalyzed C—S cross‐coupling and formation of S—F bond. A variety of functional groups including amino acids, heterocycles, halides are well tolerated. Herein, we report the first method for electrochemical synthesis of sulfonyl fluorides with triethylamine hydrofluoride as a fluorine source. These electricity‐driven reactions of odorless sulfinic salts were carried out under oxidant‐free conditions. Aryl, aliphatic, and alkenyl sulfonyl fluorides could be accessed by means of this method. In addition, we report a one‐pot protocol for Pd‐catalyzed C—S cross‐coupling and oxidative fluorination under electrochemical conditions. A reaction pathway involving the supporting electrolyte is proposed.