“Weak interaction” accelerates functionalization of hydrocarbons

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April 17, 2024

Borylation catalyzed by iridium / spirobipyridine

The RIKEN CSRS found that an iridium (Ir) catalyst having a spirobipyridine (SpiroBpy) ligand shows high catalytic activity for the functionalization of arenes.

Developing highly active catalysts for rapid and efficient synthesis of target compounds is essential to achieving sustainable organic synthesis. Hydrocarbons are an abundant carbon resource on Earth, but they have low reactivity. Therefore, highly active catalysts are necessary in order to functionalize these compunds. The direct borylation of arenes using an iridium catalyst bearing a bipyridine ligand is an important reaction with many applications in organic synthesis. However, this reaction proceeds poorly when electron-rich arenes are used as the stoichiometric substrate.

In this study, the research team has successfully developed a method for the efficient borylation of a wide variety of arenes, including electron-rich substrates, by using an iridium catalyst and a SpiroBpy ligand. This catalyst is more efficient than the previously reported catalysts, and can be used to functionalize complex pharmaceutical molecules on a gram scale.

Theoretical investigations and a kinetic isotope effect study using a deuterium-labeled ligand suggested that a noncovalent interaction between a C-H bond of the SpiroBpy ligand and the p electrons of the substrate is responsible for the accelerating effect. The results of this research will contribute to the development of rapid and efficient methods for the synthesis of pharmaceutical and agricultural compounds and functional organic molecules.

Original article
Nature Communications doi: 10.1038/s41467-024-46893-6
Y. Jin, B. Ramadoss, S. Asako, L. Ilies,
"Noncovalent Interaction with a Spirobipyridine Ligand Enables Efficient Iridium-Catalyzed C-H Activation".
Laurean Ilies; Team Leader
Sobi Asako; Senior Scientist
Advanced Organic Synthesis Research Team