Ligand-Enabled Regioselective Cross-Coupling of Palladacycles with Aryl Halides via C–H Activation

The annulation of palladacycles with <i>ortho</i>-substituted haloarenes via C-H activation represents an efficient strategy for constructing cyclic compounds. However, low regioselectivity in such reactions has limited their broader application in organic synthesis. Herein, we report a palladium-catalyzed, regioselective cross-coupling reaction of 1-(2-iodophenyl)-1<i>H</i>-pyrroles with 2-chlorobenzoic acids. Using P(2,6-(OMe)₂-Ph)₃ as a ligand, palladacycles generated via C-H activation undergo dual cross-coupling with 2-chlorobenzoic acids with excellent regioselectivity, affording pyrrolo[1,2<i>-f</i>]phenanthridine products. This method provides convenient access to a diverse range of pyrrolo[1,2<i>-f</i>]phenanthridine derivatives.