Nitromethane-Enabled Fluorination of Styrenes and Arenes

The electrophilic fluorination of unsaturated compounds provides a reliable approach to the generation of organofluorides, which are used widely in agrochemicals, pharmaceuticals, and other materials. Numerous active electrophilic fluorine reagents, such as the fluorine molecule (F-2) or xenon difluoride (XeF2), have been applied in fluorination. However, these reagents suffer from their hazardous, toxic, corrosive, and poor selective properties, and the relatively weak electrophilicity of Selectfluor or N-fluorobenzenesulfonimide (NFSI) usually limits their broad applications. Herein, we disclose nitromethane (MeNO2) as an efficient activator of Selectfluor and NFSI, as well as a stabilizer of carbocations. Therefore, the fluoro-azidation, fluoroamination, fluoroesterification of styrenes, and C-H fluorination of (hetero)arenes were well realized just by the facilitation of MeNO2. The mild reaction conditions and practicability made our current method a versatile protocol for accessing organofluorides.