A light-driven protocol for the synthesis of 2,3-dihydrobenzofurans
under mild conditions is reported. Specifically, the cascade process
is initiated by the photochemical activity of allyl-functionalized
phenolate anions, generatedin situupon deprotonation
of the corresponding phenols. The reaction proceeds rapidly with reaction
times as low as 35 min, delivering a wide range of densely functionalized
products (20 examples, yields up to 69%). Mechanistic studies have
also been performed providing convincing evidence for the photochemical
formation of carbon-centered radical species. A cascade reaction pathway
involving a tandem atom transfer radical addition (ATRA) and an intramolecular
nucleophilic substitution (SN) process is proposed to occur.