Silver-catalyzed direct selanylation of indoles: synthesis and mechanistic insights

Herein we describe the Ag(i)-catalyzed direct selanylation of indoles with diorganoyl diselenides. The reaction gave 3-selanylindoles with high regioselectivity and also allowed direct access to 2-selanylindoles when the C3 position of the indole ring was blocked via a process similar to Plancher rearrangement. Experimental analyses and density functional theory calculations were carried out in order to picture the reaction mechanism. Among the pathways considered (via concerted metalation-deprotonation, Ag(iii), radical, and electrophilic aromatic substitution), our findings support a classic electrophilic aromatic substitution via Lewis adducts between Ag(i) and diorganoyl diselenides. The results also afforded new insights into the interactions between Ag(i) and diorganoyl diselenides.

Automated summary

In this article, the Ag(i)-catalyzed direct selanylation of indoles with diorganoyl diselenides is described. The reaction efficiently yielded 3-selanylindoles with high regioselectivity, and it also provided direct access to 2-selanylindoles through a Plancher rearrangement-like process when the C3 position of the indole ring was blocked. Experimental analyses and density functional theory calculations were employed to elucidate the reaction mechanism. Among the considered pathways, our findings support a classic electrophilic aromatic substitution via Lewis adducts between Ag(i) and diorganoyl diselenides. The results also offer new insights into the interactions between Ag(i) and diorganoyl diselenides.