Abstract
Radical chain initiation strategies are fundamental to the synthesis of small molecule drugs and macromolecular materials. Modern methods for initiation through one-electron reduction are largely dominated by photo- and electrochemistry but the large-scale industrial application of these methods is often hampered by scalability challenges. Here we report a general, thermally driven and scalable method for the reductive initiation of radical chains that involves reacting an inexpensive azo initiator with a formate salt to form a carbon dioxide radical anion. Substoichiometric quantities of this initiator system were used to form C(sp (2))-C(sp (3)), C(sp (2))-S, C(sp (2))-H, C(sp (2))-B and C(sp (2))-P bonds from complex (hetero)aryl halides, with high chemoselectivity and under transition-metal-free conditions. The developed initiator system was also used to probe the mechanism of other radical reactions.