Tandem cyclisation of vinyl radicals: a sustainable approach to indolines utilizing visible-light photoredox catalysis

A tin-free method for the synthesis of substituted indolines has been developed generating vinyl radicals by visible-light-promoted photocatalysis in a reductive quenching cycle. This strategy offers a mild, robust, and high yielding pathway to a wide range of indolines containing diverse electronic substituents. The so obtained 2,3-disubstituted indolines serve as valuable precursors for the synthesis of biologically active molecules, which is demonstrated with the formal synthesis of tryptamines and furoindolines.