TMSOTf-Catalyzed Reactions of N -Arylynamides with Sulfilimines To Construct 2-Aminoindoles and α-Arylated Amidines.

Here, we disclose an efficient TMSOTf-catalyzed C-H annulation of aryl-terminated N -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 N -arylynamides undergo TMSOTf-catalyzed aminative arylation with sulfilimines providing α-arylated amidines.