Threefold annulation to diindolo[1,2-a:2',1'-c]quinoxaline via C-F bond functionalization.

A transition-metal-free, one-pot threefold annulation of ortho-difluorobenzenes with 1,3-diynyl dianilines is reported for the synthesis of diindoloquinoxalines in up to 72% yield. This cascade integrates two C-F aminations and two alkyne-amine cyclizations in a single reaction system, with the final ring closed by an intramolecular SNAr. The process is promoted by conformational locking of the substrate scaffold and enhanced effective molarity. The second SNAr is synergistically driven by preorganization of the reacting centers, the leaving ability of fluoride, and electronic effects. The substrate scope primarily concerns variation of the fluoroarene component and tolerates selected electron-rich, electron-withdrawing, and sterically demanding substituents, including heteroarenes. A sustainable platform for functional aza-polycyclic aromatics is thus provided.