An Electron-Deficient CpE Iridium(III) Catalyst: Synthesis, Characterization, and Application to Ether-Directed C–H Amidation
Eiki Tomita, Masahiro Kojima, Yuki Nagashima, Ken Tanaka, Haruki Sugiyama, Yasutomo Segawa, Atsushi Furukawa, Katsumi Maenaka, Satoshi Maeda, Tatsuhiko Yoshino, Shigeki Matsunaga*
Angew. Chem. Int. Ed. 2023, DOI: 10.1002/anie.202301259
The synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron-deficient cyclopentadienyl ligand ([CpEIrI2]2) are reported. The [CpEIrI2]2 catalyst was synthesized by complexation of a precursor of the CpE ligand with [Ir(cod)OAc]2, followed by oxidation, desilylation, and removal of the COD ligand. The electron-deficient [CpEIrI2]2 catalyst enabled C–H amidation reactions assisted by a weakly coordinating ether directing group. Experimental mechanistic studies and DFT calculations suggested that the high catalytic performance of [CpEIrI2]2 is due to its electron-deficient nature, which accelerates both C–H activation and Ir(V)-nitrenoid formation.