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 Et 3 N‐3HF complex is a liquid HF with improve safety. In this work, we report electrochemical synthesis of a series of sulfonyl fluoride with Et 3 N‐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 Et 3 N‐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.