Cu-Catalyzed and iodine mediated synthesis of thioaurones via in situ C-S bond generation using xanthate as a sulfur surrogate

An efficient method for synthesizing thioaurones has been developed using xanthate as an odorless sulfur surrogate. This reaction's key success lies in the use of iodine as a reagent, which promotes the α-iodination followed by cyclization of saturated ketones. This methodology has also been demonstrated with less reactive 2′-bromochalcones in good yield. Synthesis of the red isomer of indigo, i.e. a thia-analog of indirubin, was also achieved.