A Highly Selective Nucleophilic and Radical Relay Difluorination of Cyclopropanes and Alkenes

Fluoro-containing organic compounds have been found wide application in pharmaceutical and agrochemical industries and in medical diagnostics. In this field, the construction of C─F bonds through nucleophilic fluorination strategies remains highly challenging. Herein, we have developed a radical-polar strategy for visible-light-induced nucleophilic fluorination and subsequent radical fluorination, allowing for direct difluorination of cyclopropanes and styrenes under mild reaction conditions. It affords a series of structurally diverse, both 1,3- and 1,2-difluorinated products in synthetically useful yields by means of ∼0.1 mol% of 4CzIPN as catalyst. Furthermore, only 3 equivalents of Et₃N·3HF are required to realize an efficient nucleophilic fluorination, while 1.7 equivalents of Selectfluor are used as the radical fluorinating source, demonstrating good functional group compatibility and thus can be applied in late-stage difluorination of complex molecules.