Metal Free Benzylation and Alkylation of Quinoxalin-2(1H)-ones with Alkenes Triggered by Sulfonyl Radical Generated from Sulfinic Acids

A metal-free domino multicomponent reaction for the direct C-H benzylation and alkylation of quinoxalin-2(1H)-ones using alkenes is described. Triggered by the sulfonyl radical generated from sulfinic acid, the alkenes are transformed to alkyl radicals that react exclusively at the C-3 position of quinoxalin-2(1H)-ones. Importantly, the method not only functionalizes medicinally important quinoxalin-2(1H)-one scaffold, but also furnishes diverse medicinally relevant sulfones in good to excellent yields under mild conditions.