Mixed Directing‐Group Strategy: Oxidative C−H/C−H Bond Arylation of Unactivated Arenes by Cobalt Catalysis

A mixed directing‐group strategy for inexpensive [Co(acac) 3 ]‐catalyzed oxidative C−H/C−H bond arylation of unactivated arenes has been disclosed. This strategy enables the arylation of a wide range of benzamide and arylpyridines effectively to afford novel bifunctionalized biaryls, which are difficult to achieve by common synthetic routes. Two different pathways, namely, a single‐electron‐transmetalation process (8‐aminoquinoline‐directed) and a concerted metalation–deprotonation process (pyridine‐directed), were involved to activate two different inert aromatic C−H bonds. Moreover, the aryl radicals have been trapped by 2,6‐di‐ tert ‐butyl‐4‐methylphenol to form benzylated products. This unique strategy should be useful in the design of other arene C−H/C−H cross‐couplings as well.