Nickel Meets Aryl Thianthrenium Salts: Ni(I)-Catalyzed Halogenation of Arenes.

Herein, a regioselective, late-stage two-step arene halogenation method is reported. We propose how unusual Ni(I)/(III) catalysis is enabled by a combination of aryl thianthrenium and Ni redox properties that is hitherto unachieved with other (pseudo)halides. The catalyst is accessed in situ from inexpensive NiCl 2 ·6(H 2 O) and zinc without the need of supporting ligands.