Palladium‐Catalyzed Direct Monoarylation of Aryl C−H Bonds with Iodoarenes

The transition-metal-catalyzed direct arylation of nonactivated aryl C-H bonds with iodoarenes has emerged as an important method for the construction of biaryls. Generally, the direct arylation reaction proceeds in the presence of stoichiometric Ag additives; moreover, the diarylation product is often unavoidable if there are two identical aromatic C-H bonds in the substrate. Herein we disclose an efficient Pd(OAc)(2)/trifluoroacetic acid/O-2 catalytic system that promotes direct arylation reactions of a variety of aromatic C-H bonds with diverse iodoarenes under Ag-free conditions. The coupling reaction possesses a complete monoarylation selectivity. This approach provides a straightforward, facile, and economical route to biaryls.