Synthesis of Quinoline–Indole Hybrids through Cu(II)-Catalyzed Amination and Annulation between <i>N</i>‑Oxides and <i>o</i>‑Alkynylanilines

The synthesis of (iso)quinoline-indole hybrids by reacting (iso)quinoline N-oxides with o-alkynylanilines in the presence of a combination of copper(II) catalyst and a bidentate 2,2′-bipyridine ligand is described. The utility of this method was demonstrated through site-selective functionalization of the synthesized products. A plausible reaction pathway for site-selective amination followed by annulative indole formation was elucidated by a series of mechanistic investigations.