Visible light-induced cascade cyclization of 2-isocyanoaryl thioethers/selenoethers: access to 2-arylthiobenzothiazoles/2-arylthiobenzoselenazoles.

Herein, we describe an efficient and atom-economical strategy for the synthesis of 2-arylthiobenzothiazole and 2-arylthiobenzoselenazole compounds via visible light-induced cascade cyclization of 2-isocyanoaryl thioethers/selenoethers with diaryl disulfides. Among them, two C-X (X = S, Se) bonds were formed under mild conditions in one single operation through thiyl radical addition to the isocyano groups of 2-isocyanoaryl thioethers/selenoethers followed by an annulation process. This protocol features excellent chemical selectivity, good functional group tolerance, simple operation and mild reaction conditions. Moreover, the derivatization reaction of the newly formed 2-arylthiobenzothiazole products demonstrates the utility of this method in organic synthesis.