Peroxide-mediated radical cyclization

Zard also used a xanthate-mediated radical cascade sequence to synthesize indolines from vinyl sulfanilides in three steps [54]. The initial peroxide-initiated intermolecular addition of the xanthate to the vinyl sulfanilide was followed by an intramolecular cyclization onto the ortho position of the aromatic ring. Further heating with DBU generated the dihydroindole through a base-induced isomerization of the olefinic bond followed by conjugate addition. 

---