Visible Light-Induced Hydroxyalkylation of 1,2,4-Triazine-3,5(2H,4H)-dione with Alcohols via Oxidative Cross-Dehydrogenative-Coupling

An unprecedented C6–H hydroxyalkylation of 1,2,4-triazine-3,5(2H,4H)-dione was achieved using readily available and inexpensive alcohols as the coupling partner, low-toxicity 2-tert-butylanthraquinone as the photocatalyst, sodium bicarbonate as the base, and air as the green oxidant via oxidative cross-dehydrogenative-coupling. The reaction conditions are mildly carried out under visible-light induction with good functional group tolerance and a wide substrate scope. A series of mechanistic exploration experiments demonstrated that the reaction proceeds via a radical mechanism. In addition, gram-scale experiments and application studies indicated that this method has a bright practical prospect.