Visible-Light-Mediated Borylation of Arenes via an Electron Donor–Acceptor Complex of Thianthrenium Salts

Aryl borates are one of the most important synthetic materials in organic synthesis. Herein, we report a visible-light-induced electron donor-acceptor (EDA)-based borylation protocol between thianthrenium salts and 1,4-diazabicyclo[2.2.2]octane (DABCO) for the synthesis of various aryl boronates without a photocatalyst or stepwise processing. Remarkably, this photochemical strategy is compatible with a wide range of sensitive functional groups and affords excellent yields. Moreover, the quantitative recovery of thianthrene for feedstock synthesis lowers the reaction cost.