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.