Equivalent Loading of Directed Arenes in Pd(II)-Catalyzed Oxidative Cross-Coupling of Aryl C-H Bonds at Room Temperature

The unsymmetrical biaryls (Ar-1-Ar-2) produced by the catalytic cross-couplings of aryl halides (Ar-1-halo) with aryl metallics (Ar-2-M) in the loading ratio of 1:1 are popular in chemical synthesis. In contrast, there has been less precedence on the same biaryls produced effectively from two normal aryl C-H bonds with equivalent loading. Here, we report that, in a palladium/oxidant/acid catalytic system at room temperature, one arene (Ar-1-H, 1 equiv) can highly selectively couple with the other one (Ar-2-H, 1 equiv) to afford the target Ar-1-Ar-2 just by controlling the directing groups and the substituted groups on their phenyl rings. The utility of this one-one cross-coupling is also demonstrated by synthesis of a few bioactive molecules.