Development of a Highly Efficient Iridium Catalyst

January 23, 2025

Controlling Reactions Through Substrate Recognition via Hydrogen Bonding

The direct functionalization of organic molecules enables the efficient synthesis of pharmaceuticals and functional materials in fewer steps and enhances structural diversity in the final stages of synthesis. These methods typically use transition metal catalysts such as iridium (Ir), which can efficiently activate the inert carbon-hydrogen (C–H) bond in an organic molecule.

One of the key challenges for these reactions is selectively introducing a functional group only at the targeted C−H site. Researchers at the RIKEN CSRS have successfully developed a site-selective and efficient borylation reaction for pyridine derivatives, by designing a novel iridium (Ir) catalyst bearing a hydroxylated spirobipyridine (SpiroBpy-OH) ligand. This catalyst recognizes the pyridine substrates through hydrogen bonding to control the site selectivity in a switchable manner, accelerate the reaction, and differentiate between different substrates, reminiscent of enzymatic catalysis.

Pyridine derivatives are heteroaromatic compounds containing a nitrogen atom and are commonly found in the core structures of natural products and pharmaceuticals. Therefore, this research is expected to contribute to the development of efficient synthetic methods for agrochemicals, pharmaceuticals, and functional molecules, while also providing new design principles for catalysts that recognize a substrate through noncovalent interactions such as hydrogen bonding.

Original article

Angewandte Chemie International Edition　doi: 10.1002/anie.202419144

P. B. De, K. Okamoto, J. Sekar, S. Asako, L. Ilies,

"Remote Hydrogen Bonding Between Ligand and Substrate Accelerates C-H Bond Activation and Enables Switchable Site Selectivity".

Contact

Laurean Ilies; Team Leader
Sobi Asako; Senior Scientist
Advanced Organic Synthesis Research Team