Visible-Light-Driven Synthesis of 4-Alkyl/Aryl-2-Aminothiazoles Promoted by In Situ Generated Copper Photocatalyst

Room-temperature synthesis of 4-alkyl/aryl-2-aminothiazoles from vinyl azides and ammonium thiocyanate was accomplished with the aid of copper salts and blue LED irradiation. Mechanism investigation indicates that in situ formed Cu(NCS)(2)(-) plays dual important roles in the reaction: (1) as the photocatalyst to activate vinyl azides, (2) as the Lewis acid catalyst to promote ring opening of 2H-azirines with thiocyanide. This process is distinguished by high yields, mild conditions, low catalyst loadings, and tolerating numerous alkyl- and aryl vinyl azides with an array of functional groups.