Silver-Catalyzed Remote C5-H Selenylation of Indoles.

Remote C-H functionalization at C5 is the most sparingly observed selectivity in the functionalization of indole templates. Herein, we reported that the combination of a AgSbF6 catalyst and phenyliodine diacetate oxidation enabled the C-H selenylation at the C5 position of indole scaffolds in a selective version, thus leading to the formation of a wide scope of 5-selenylated indole derivatives, which are otherwise difficult to prepare. Mechanistic studies indicated that current transformation follows a radical process, and the tethered C3 pivaloyl group on indole scaffolds plays roles in both blocking the active C3 position and manipulating the electronic affinity of the arenes.