Electron-Deficient CpRh(III)-Catalyzed C–H Functionalization of <i>N</i>-2-Pyridylanilines: Branch-Selective Alkenylation with Alkenes and Annulation with Alkynes

We report the electron-deficient CpRh(III) [Cp^ERh(III)] complex-catalyzed branch selective alkenylation with aliphatic alkenes and annulation with internal alkynes using <i>N</i>-2-pyridylanilines. In these reactions, the electron-deficient Cp^ERh(III) catalyst is more active than the electron-rich Cp*Rh(III) catalyst, used commonly in C-H activation, and the reactions proceed with a catalytic amount of a Cu(II) oxidant under air and at lower temperatures than conventional methods. From mechanistic considerations, steric repulsion between the ligand and the directing group may be responsible for the branch selective alkenylation.