A synthetic methodology for the late-stage ortho-C–H bond aroylation of anilines with aryl aldehydes led to a variety of ortho-aroylated anilines by the use of palladium­(II) acetate, tert-butyl hydroperoxide, and 1,4-dioxane as the catalyst, oxidant, and solvent, respectively, is presented. An N-phenylpyridin-2-amine palladacycle was isolated and characterized by X-ray crystallography. Controlled experiments, radical trapping experiments, and the experiments of the kinetic isotope effect were undertaken to support the proposed reaction mechanism. Syntheses of 2-aminobenzophenone and 9­(10H)-acridanone based on the developed methodology were successfully demonstrated.

We present a stoichiometric methodology for the synthesis of 4-arylated/alkylated 9­(10H)-acridinones via a palladium-mediated ortho-C–H bond activation and C–C bond cross-coupling strategy. In the reaction, a N-(pyridin-2-yl)-9­(10H)-acridinone palladacycle was employed as the starting substrate, which could be readily prepared by the stoichiometric reaction of N-(pyridin-2-yl)-9­(10H)-acridinone and palladium­(II) acetate in 89% isolated yield. Meanwhile, potassium aryl/alkyltrifluoroborates and p-benzoquinone were introduced to serve as the coupling partner and reaction promoter, respectively, in the presented palladium-mediated ortho-C–H bond arylation/alkylation of 9­(10H)-acridinone. The reaction eventually furnished a variety of 4-arylated/alkylated 9­(10H)-acridinones in 31–95% yields. The structures of N-(pyridin-2-yl)-9­(10H)-acridinone palladacycle substrate and 4-phenylated/cyclopropylated 9­(10H)-acridinone products were elucidated by X-ray crystallography. Kinetic isotope effect studies, as well as controlled experiments, were carried out to gain insight into the reaction mechanism. Finally, the removal of the directing group (i.e., pyridin-2-yl) was demonstrated on one of the ortho-arylated products, 4-phenyl-N-(pyridin-2-yl)-9­(10H)-acridinone.

A facile and efficient synthetic methodology for preparing dibenzosuberones via a C−H bond activation strategy is presented. The ortho-aroylated 3,5-diarylisoxazole was employed as the starting substrate to undergo palladium-catalyzed intramolecular C−H/C−Br bond crosscoupling to produce a variety of dibenzosuberones bearing an isoxazole group in 24 to >99% 1 H NMR yields. The dibenzosuberone structure was further confirmed by X-ray crystallography. The developed methodology exhibits very good functional group tolerance. In addition, a rational mechanism was presented for describing the reaction process. For the prepared dibenzosuberone, the use of Mo(CO) 6 as the catalyst can easily transform the isoxazole ring into the β-aminoenone group. Finally, the structure of the anticipated ring-opening product, dibenzosuberenone, bearing a β-amino-α-ketone group was secured by X-ray crystallography.