Electrochemical Synthesis of S- Aryl Dibenzothiophenium Triflates as Precursors for Selective Nucleophilic Aromatic (Radio)fluorination.

A novel electrosynthetic approach to aryl dibenzothiophenium salts, including the direct intramolecular formation of a C-S bond in a metal-free, electrochemical key step under ambient conditions, is reported. The broad applicability of this method is demonstrated with 14 examples, including nitrogen-containing heterocycles in isolated yields up to 72%. The resulting sulfonium salts can be used as precursors for fluorine labeling to give [ 18 F]fluoroarenes as found in PET tracer ligands.