Chemists develop “Dump-and-Stir” technique for fast and safe carborane synthesis

Osaka, Japan – Researchers from The University of Osaka have developed a groundbreaking synthetic method that makes reliably and efficiently incorporating boron-rich carborane clusters into aromatic compounds as simple as “mixing and heating.” This innovation eliminates the need for complex, hazardous steps that have long limited the practical use of carborane chemistry.

Carboranes—icosahedral clusters composed of boron and carbon atoms—are prized for their exceptional stability, unique three-dimensional aromaticity, and ability to capture neutrons. These properties make them highly promising for boron neutron capture therapy (BNCT), functional materials, and drug design. However, existing methods for attaching carboranes to aromatic frameworks required intricate multi-step reactions under harsh conditions, accessible only to highly skilled chemists.

A research team, led by Dr. Yoichi Hoshimoto successfully synthesized a stable reagent named lithium bis(ortho-carboranyl) cuprate (Li/Cu-1). Using this reagent, aromatic compounds can be transformed into carborane-containing molecules simply by combining and heating them—what the researchers call a “dump-and-stir” process. This approach enables large-scale, high-yield production using inexpensive aryl bromides and chlorides, replacing the previously required hazardous reagents and low-temperature operations.

This user-friendly, scalable technique marks a major advance toward the broader application of carborane chemistry in medicine, materials science, and sustainable manufacturing.

“Our method is like ready-made meals –made everyday life richer– for synthetic chemists—you just mix, heat, and it’s done,” says Dr. Hoshimoto, the corresponding author of the study. “We believe this simple approach will empower many more scientists to explore the field of carborane chemistry. With this achievement, an instant synthesis method for carborane-containing molecules—one that could reshape the future—has been realized.”

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The article, “An Isolated Lithium ortho-Carboranyl Cuprate Complex for the Synthesis of Multiple-Carborane-Substituted Arenes from (Hetero)Aryl Bromides and Chlorides,” was published in Journal of the American Chemical Society at DOI:  https://doi.org/10.1021/jacs.5c13004

About The University of Osaka

The University of Osaka was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, The University of Osaka is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

Website: https://resou.osaka-u.ac.jp/en