Rhodium(III)-Catalyzed Selective Monoarylation of β or γ C(sp)-H Bonds Assisted by a Trimethylpyrazole Group.

The selective arylation of unactivated β or challenging γ primary and secondary β-C(sp)-H bonds has been developed with a Cp*Rh(III) catalyst assisted by a trimethylpyrazole group. A rarely reported six-membered rhodacycle has been identified in rhodium-catalyzed C(sp)-H activation reactions. Preliminary mechanistic studies have revealed that a concerted metalation-deprotonation pathway might be involved in the C-H activation step.