Photoinduced transition-metal and external photosensitizer free phosphonation of unactivated C(sp^(2))-F bond via SET process under mild conditions

Transition-metal catalyzed cross-couplings of aryl halides(ArI,ArBr and ArCl)with a broad range of nucleophiles have been developed as powerful methods for carbon-carbon and carbon-heteroatom bonds formation.However,due to the high bond dissociation energy of unactivated C(sp^(2))-F,cross-couplings of mono-fluoroarenes are the most challenging,especially without using transition-metal catalysts.Herein,a photo-induced transition-metal and external photosensitizer free defluorophosphonation of monofluoroarenes via unactivated C(sp^(2))-F bond cleavage is reported.Different mono-fluoroarenes have been successfully cross-coupled with dialkyl phosphites in moderate to excellent yields under mild conditions.Mechanistic studies have revealed the possible involvement of a photo-induced SET process and aryl free radical intermediates.