Erythrosine B Catalyzed Synthesis of trans-Dihydro-4H-furo[3,2-c]- chromen-4-ones through Photocatalytic Dehydrogenative sp3 C-O Bond Formation

A simple and efficient visible-light-induced methodology has been developed for the selective synthesis of dihydro-4H-furo[3,2-c]chromen-4-one derivatives via dehydrogenative coupling reaction. The methodology is highly useful for the synthesis of varieties of dihy-dro-4H-furo[3,2-c]chromen-4-ones from readily accessible reactants under oxygen atmosphere. Importantly, the additive-free approach has been also demonstrated for this transformation. The results of the mechanistic investigation showed that this dehydrogenative reaction proceeded through a radical pathway. Additionally, the synthesized di-hydro-4H-furo[3,2-c]chromen-4-one has been transformed into differ-ent 4H-furo[3,2-c]chromen-4-ones through simple protocols.