Rhodium-Catalyzed Atroposelective C-H Arylation of (Hetero)Arenes Using Carbene Precursors as Arylating Reagents.

Rhodium(III)-catalyzed C-H activation-based arylation of sterically hindered (hetero)arenes has been realized using diazo compounds and triazoles as arylating reagents for atroposelective synthesis of two classes of biaryls. The coupling of 3-substituted indoles and -sulfonyltriazoles afforded indoles with a C(2)-C chiral axis, while the arylation of 1-naphthylthioether with -quinone diazide afforded chiral binaphthyls. These coupling systems proceeded under mild conditions via C-H activation and carbene insertion despite the steric hindrance of both the arenes and the carbene precursors.