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

Abstract

The photo-induced mild three-component thiocyanation/selenocyanation-cyclization-rearrangement of indole-tethered 1,6-enynes with NH₄SCN/KSeCN and O₂ was developed to access diverse thiocyanated/selenocyanated bicarbonyl pyrrolo[1,2-a]indoles. O₂ served both as an oxidant and a 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 transformations was conducted to assess product utility. Finally, detailed mechanistic studies (such as isotopic labeling, radical inhibition/capture, on/off light switching, and fluorescence-quenching experiments) revealed a plausible reaction mechanism for this tandem system.