Oxidative Control of Photoinduced Cascade Electrocyclizations in Aromatic Azido Imines to Access Complex Fused Imidazoles or Pyrazoles.

Photoinduced cascade of two 6π-electron six- and five-center electrocyclizations in aromatic azido imines is oxidatively controlled to yield complex fused benzimidazoles or indazoles. Formation of benzimidazoles occurs via an unprecedented carbon-to-nitrogen o -iminoaryl 1,2-shift.