I₂/PIDA Mediated Regioselective Metal-Free Synthesis of Aryl Selenoether-Linked Trisubstituted Thiazoles

A regioselective metal-free C-Se bond-forming methodology for the preparation of trisubstituted thiazoles linked with aryl selenoethers has been developed from the reaction of disubstituted thiazoles and diaryl diselenides in the presence of 20 mol % molecular iodine and PIDA as an oxidant in DMF medium. A wide range of disubstituted thiazoles bearing two aryl or aryl and coumarin moieties was found suitable for this transformation. The notable features of this method are sp²-C-H functionalization of the C-5 position of the thiazole, metal-free conditions, a wide substrate scope, regioselective product, as well as the presence of medicinally important thiazole and aryl selenoether moieties in the products.