Pd(II)-Catalyzed Ortho Trifluoromethylation of Arenes and Insights into the Coordination Mode of Acidic Amide Directing Groups

A Pd­(II)-catalyzed trifluoromethylation of ortho C–H bonds with an array of N-arylbenzamides derived from benzoic acids is reported. N-Methylformamide has been identified as a crucial promoter of C–CF3 bond formation from the Pd center. X-ray characterization of the C–H insertion intermediate has revealed a rare coordination mode of acidic amides as directing groups and the origin of their capacity in directing C–H activation.