Progress in the preparation of organo-fluorine compounds using HF or HF–base molten salts

Hydrogen fluoride (HF) combined with organic bases (HF-base molten salts) has been successfully developed as a novel methodology for the fluorination of organic compounds, in particular, with regards to the selective hydrofluorination, halogen-exchange fluorination, deaminative fluorination of aminoarenes, and electrochemical oxidative fluorination. Also, arene iodine difluoride (ArIF2), prepared electrochemically from iodoarenes in HF-base molten salts, was found to be useful for the introduction of a fluorine atom to organic molecules. Furthermore, the reaction of fluoro-alkenyl-iodonium salts, derived from ArIF2 and alkynes in HF-base molten salts, was developed for the stereo- and regioselective synthesis of α-fluoroalkenes.