Co(III)-Catalyzed C–H Activation/Formal SN‑Type Reactions: Selective and Efficient Cyanation, Halogenation, and Allylation

The first cobalt-catalyzed cyanation, halogenation, and allylation via C–H activation have been realized. These formal SN-type reactions generate valuable (hetero)­aryl/​alkenyl nitriles, iodides, and bromides as well as allylated indoles using a bench-stable Co­(III) catalyst. High regio- and mono-selectivity were achieved for these reactions. Additionally, allylation proceeded efficiently with a turnover number of 2200 at room temperature, which is unprecedented for this Co­(III) catalyst. Alkenyl substrates and amides have been successfully utilized in Cp*Co­(III)-catalyzed C–H activation for the first time.