Copper-Catalyzed\n[3 + 2] Annulation of <i>O</i>‑Acyl Oximes with <i>p</i>‑Hydroquinones\nfor the Synthesis of 5‑Hydroxyindoles

A copper-catalyzed\n[3 + 2] annulation of <i>O</i>-acyl\noximes with 2-electron-withdrawing group substituted <i>p</i>-hydroquinones for the efficient synthesis of polysubstituted 5-hydroxyindoles\nis developed. Further intramolecular cyclization leads to the concise\nand rapid construction of several kinds of 3,4- and 4,5-fused polycyclic\nindoles.