Dearomative Indole Annulation with 2-Aminoaryldisulfide – an Approach for Accessing Polycyclic Indoline-Fused-Benzothiazine

Herein, we develop a practical protocol for the dearomative annulation of indoles with 2-aminoaryl disulfides under mild conditions for accessing three-dimensional (3D) indoline frameworks. The developed protocol shows remarkable tolerance toward different functional groups. Additionally, this method was applied for the late-stage modification of drugs and natural products. Mechanistic studies reveal that this reaction proceeds via the activation of aryl disulfide by NFSI, generating an electrophilic sulfur as a key intermediate.