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

doi:10.1002/anie.202301259

An Electron-Deficient Cp^E Iridium(III) Catalyst: Synthesis, Characterization, and Application to Ether-Directed C-H Amidation

Angew Chem Int Ed Engl. 2023 May 15;62(21):e202301259. doi: 10.1002/anie.202301259. Epub 2023 Apr 14.

Authors

Eiki Tomita¹, Masahiro Kojima¹, Yuki Nagashima², Ken Tanaka², Haruki Sugiyama^{3

4}, Yasutomo Segawa^{3

4}, Atsushi Furukawa^{1

5}, Katsumi Maenaka^{1

6}, Satoshi Maeda^{7

8

9}, Tatsuhiko Yoshino^{1

6}, Shigeki Matsunaga^{1

6}

Affiliations

¹ Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812, Japan.
² Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan.
³ Institute for Molecular Science, Okazaki, 444-8787, Japan.
⁴ Department of Structural Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, 444-8787, Japan.
⁵ Current address: Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
⁶ Global Station for Biosurfaces and Drug Discovery, Hokkaido University, Kita-ku, Sapporo, 060-0812, Japan.
⁷ Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita-ku, Sapporo 001-0021, Japan.
⁸ Department of Chemistry, Faculty of Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan.
⁹ JST, ERATO Maeda Artificial Intelligence for Chemical Reaction Design and Discovery Project, Kita-ku, Sapporo, 060-0810, Japan.

PMID: 36918357
DOI: 10.1002/anie.202301259

Abstract

The synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron-deficient cyclopentadienyl ligand ([Cp^E IrI₂ ]₂ ) are reported. The [Cp^E IrI₂ ]₂ catalyst was synthesized by complexation of a precursor of the Cp^E ligand with [Ir(cod)OAc]₂ , followed by oxidation, desilylation, and removal of the COD ligand. The electron-deficient [Cp^E IrI₂ ]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 [Cp^E IrI₂ ]₂ is due to its electron-deficient nature, which accelerates both C-H activation and Ir^V -nitrenoid formation.

Keywords: Amidation; CpE Ligand; C−H Activation; Ether Directing Group; Iridium.

Abstract

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