Visible Light-Mediated Coupling of Thioureas and 1,3-Dicarbonyls: Towards a Leaving Group-Free Synthesis of Aminothiazoles

A synthesis of aminothiazoles from various 1,3-dicarbonyls and thioureas without a leaving group has been developed. The reaction is photocatalyzed by tetraiodofluorescein, an organic dye. Under irradiation with green LEDs, a sulfur radical is generated insitu from thiourea, followed by addition to the enol tautomer, forming the aminothiazole backbone. This novel strategy provides a greener alternative to the traditional leaving group protocols, with excellent atom economy.