Photo-induced thio/selenocyanation-annulation-rearrangement of indole-tethered 1,6-enynes

Abstract

Photo-involved mild three-component thiocyanation/selenocyanation-cyclization-rearrangement of indole-tethered 1,6-enynes, NH4SCN/KSeCN, with O2 was developed to access diverse thiocyanated/selenocyanated bicarbonyl pyrrolo[1,2-a]indoles. O2 acted in dual roles (oxidant and dicarbonyl oxygen source). The rearrangement of the stable indole scaffold smoothly introduced multiple substituents. In addition, a range of scaled-up operations and active-skeleton transformation was operated to test the product application. Finally, detailed mechanistic studies (such as isotopic labeling, radical inhibition/capturation, on/off light, and fluorescence-quenching experiments) revealed the plausible reaction process of this tandem system.