Iridium(III) Catalysts with an Amide-Pendant Cyclopentadienyl Ligand: Double Aromatic Homologation Reactions of Benzamides by Fourfold C-H Activation.

The synthesis, characterization, and catalytic performance of iridium(III) catalysts that bear an amide-pendant cyclopentadienyl ligand ([CpA IrI2 ]2 ) is reported. These [CpA IrI2 ]2 catalysts were obtained from the complexation of a CpA ligand precursor with [Ir(cod)OAc]2 followed by oxidation. Double aromatic homologation reactions of benzamides with alkynes by fourfold C-H activation proceeded in good to high yield with these [CpA IrI2 ]2 catalysts, demonstrating their superior catalytic performance in this challenging transformation.