Visible-Light-Driven Multicomponent Radical Cascade Versatile Alkylation of Quinoxalinones Enabled by Electron Donor Acceptor Complex in Water

An operationally simple aqueous phase three-component photochemical strategy for the alkylation of quinoxalin-2(1H)-ones with diethyl alpha-bromomalonate and unactivated alkenes in the absence of both photoredox catalysts and additive has been developed. This reaction is driven by the photochemical activity of electron donor-acceptor (EDA) complexes formed by quinoxalin-2(1H)-ones and diethyl alpha-bromomalonate. Irradiation with visible light triggered single-electron transfer (SET) from the quinoxalin-2(1H)-ones to the diethyl alpha-bromomalonate, inducing the formation of the corresponding alkyl radical and the subsequent radical tandem reaction. It provides an efficient way to construct alkylated quinoxalinones from simple small molecules.