Iodine-mediated synthesis of indole-fused benzothiazepinones through intramolecular C2-amidation of amide-tethered C3-sulfenylindoles

A transition-metal-free, iodine-mediated strategy has been developed for the synthesis of biologically significant indole-fused benzothiazepinones. This method involves an initial electrophilic C3 iodination of indole, followed by intramolecular C2 amidation of readily accessible amide-tethered C3-sulfenylindoles to afford indole-fused benzothiazepinones in good yields. The protocol exhibits broad substrate compatibility, high functional group tolerance, and scalability. Additionally, the synthetic versatility of the resulting indole-fused benzothiazepinones was demonstrated through their transformation into the corresponding sulfoxides and sulfones.