Photocatalytic Construction of S–S and C–S Bonds Promoted by Acridinium Salt: An Unexpected Pathway To Synthesize 1,2,4-Dithiazoles

An unexpected cyclization of thioamides with p-quinone methides promoted by acridinium salt under the irradiation of visible light furnished 1,2,4-dithiazoles in moderate to good yields. In addition, the reaction of the obtained 1,2,4-dithiazoles with isocyanides offered a new entry for the synthesis of thiazol-5(4 H)-imines in moderate yields.