Photo-Induced Thiocyanation/Selenothiocyanation/Cyclization of Indole-3-Carboxamides with KSCN and KSeCN under Mild Conditions

A practical and sustainable photo-induced protocol for the thiocyanation/selenothiocyanation/cyclization of indole-3-carboxamides with cost-effective potassium thiocyanate (KSCN) and potassium selenocyanate (KSeCN) has been developed. This transformation is mediated by the nontoxic organic dye Eosin B and proceeds smoothly at room temperature without the need for metals or bases, offering a practical route to a diverse array of thiocyanated and selenothiocyanated γ-carbolinone derivatives in moderate to good yields (41 examples). Notable advantages include compatibility with gram-scale operations and successful execution under sunlight, which further underscore the synthetic utility of this approach for constructing complex molecular scaffolds.