Base-Mediated Visible-Light-Driven C–H Arylation of Quinoxalin-2(1H)-Ones in Ethanol

Prior methods for visible-light-driven C–H arylation of quinoxalin-2(1H)-ones relied on external photocatalysts. Herein, we report a photocatalyst-free approach for this arylation. In this approach, β-dicarbonyl iodonium ylides, combined with t-BuOK in ethanol, act as aryl precursors, forming electron donor–acceptor (EDA) complexes. These complexes enhance light absorption, facilitating efficient single electron transfer and aryl radical formation. Consequently, various quinoxalin-2(1H)-ones undergo precise and efficient arylation without external photocatalysts. This protocol exhibits excellent tolerance toward diverse functional groups, with mild reaction conditions and eco-friendly solvents, revealing a high Ecoscale value.