Three-Component Oxyarylation of Alkenes Enables Access to C-3-Substituted Dihydrobenzofurans

A practical and modular three-component alkene oxyarylation with benzoquinone and H2O to rapidly access C-3-substituted dihydrobenzofurans has been developed. The (NH4)(2)S2O8-mediated redox-relay process has an excellent regioselectivity and functional group tolerance and exhibits a broad scope of simple alkenes, rapidly furnishing a variety of the substructures that would require multiple steps to prepare with traditional methods. Mechanistic studies revealed a dual role of benzoquinone serving as both the arylation agent and the origin of dihydroquinone for the reductive cyclization step.