Synthetic Access to 3,5,7-Trisubstituted Indoles Enabled by Iridium­-Catalyzed C–H Borylation

A one-pot conversion of 3-substituted indoles into their 5,7-diboryl derivatives is reported. The simultaneous functionalization of the C5-H and C7-H sites is achieved using an iridium-catalyzed triborylation-protodeborylation sequence. The 5,7-diborylindoles are useful intermediates that can be readily derivatized into a variety of indoles possessing the rare 3,5,7-trisubstitution pattern, including the natural product (+)-plakohypaphorine C.