Copper-Catalyzed\nHydroamination of 2‑Alkynylazobenzenes:\nSynthesis of 3‑Alkenyl‑2<i>H</i>‑Indazoles

A copper-catalyzed intramolecular synthesis of 3-alkenyl-2<i>H</i>-indazoles from 2-alkynylazobenzenes is described. The\nreaction proceeds in a single step via C–N bond formation and\na subsequent 1,2-hydride shift, affording products in high yields.\nDFT calculations suggest the 1,2-hydride shift as the rate-determining\nstep. Further derivatization enables functionalization of the 3-alkenyl-2<i>H</i>-indazoles.