Intermolecular dearomative C2-arylation of N-Ac indoles activated by FeCl3

Abstract

We report the FeCl₃-mediated direct addition of electron-rich arenes to the C2-position of electrophilic N-Ac indoles under mild conditions (room temperature, air). No functional group is required on the arene nucleophile: one of its C–H bonds is added to the C2C3 double bond of the indole nucleus in a Friedel–Crafts-type reaction. This dearomatisation process delivered a broad range of C2-arylated indolines.