Additive- and Metal-Free, Predictably 1,2-and 1,3-Regioselective, Photoinduced Dual C-H/C-X Borylation of Haloarenes

We report herein a simple, additive- and metal-free, photoinduced, dual C-H/C-X borylation of chloro-, bromo-, and iodoarenes. The reaction produces 1,2- and 1,3-diborylarenes on gram scales under batch and continuous flow conditions. The regioselectivity of the dual C-H/C-X borylation is determined by the solvent and the substituents in the parent haloarenes.