Transition-metal-free C-C, C-O and C-N cross-couplings enabled by light

Transition-metal catalyzed cross-couplings to construct C-C, C-O and C-N bonds have revolutionized chemical science. Despite the great achievements, these metal-catalysts also raise certain issues including their high cost, requirement of specialized ligands, the sensitivity to air and moisture and the so-called “transition-metal-residue issue”. Complementary strategy, which does not rely on the well-established “oxidative addition, transmetalation and reductive elimination” mechanistic paradigm, would potentially eliminate all these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols and nitriles without the assistance of metal catalysts empowered by photo energy. Control experiments reveal that among all common aryl electrophiles, only aryl triflates are competent in these couplings whereas aryl iodides and bromides can not serve as the coupling partners. DFT calculation reveals that once converted to aryl radical cation, aryl...