Photoinduced Sequential Hydrogen and Halogen Atom Transfer for Direct C–H Functionalization of Quinoxalin‐2(1H)‐ones with Alkyl Iodides

The chemoselective activation of alkyl halides under mild and sustainable conditions continues to pose an ongoing issue in C–H functionalization chemistry. A metal‐free, photoinduced sequential hydrogen atom transfer (HAT) and halogen atom transfer (XAT) method that utilizes transient boryl radicals produced in situ from stable amine‐borane adducts is presented. This platform facilitates effective C(sp 2 )–H alkylation of quinoxalin‐2(1 H )‐ones through a synergistic HAT/XAT cascade, utilizing easily accessible alkyl iodides and ambient air as the terminal oxidant. The approach demonstrates broad substrate generality, elevated regioselectivity, and favorable functional group compatibility, enabling late‐stage diversification of pharmaceutically significant heterocycles under operationally simple conditions.