TMSOTf-Catalyzed Reactions of <i>N</i>‑Arylynamides with Sulfilimines To Construct 2‑Aminoindoles and α‑Arylated Amidines

Here, we disclose an efficient TMSOTf-catalyzed C–H annulation of aryl-terminated <i>N</i>-arylynamides with sulfilimines, leading to the practical assembly of various valuable 2-aminoindoles in generally moderate to excellent yields with a broad range of functional groups, while nonaryl terminated <i>N</i>-arylynamides undergo TMSOTf-catalyzed aminative arylation with sulfilimines providing α-arylated amidines.