Oct 7: French chemist Henri B. Kagan and Japanese chemist Kenso Soai have been awarded the 2026 Nobel Prize in Chemistry for pioneering discoveries that helped explain how molecular asymmetry, or homochirality, can emerge naturally.
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The Royal Swedish Academy of Sciences announced the award on Wednesday, recognising the scientists for their groundbreaking work on non-linear effects and autocatalysis in asymmetric organic synthesis.
The two laureates will share a prize of 12 million Swedish kronor.
Breakthrough in a Long-Standing Chemical Puzzle
Many molecules found in nature, including amino acids, occur in two forms that are mirror images of each other. Although these forms have nearly identical chemical properties, living organisms overwhelmingly rely on only one of them.
This phenomenon, known as homochirality, has puzzled scientists for more than a century.
In conventional laboratory reactions, chemists often obtain roughly equal quantities of both mirror-image forms. Kagan and Soai’s research demonstrated that chemical reactions can instead be directed to strongly favour one molecular form, and in certain cases produce virtually only one.
“Henri Kagan and Kenso Soai have provided a solution to a chemical mystery that is over a century old: how homochirality can emerge spontaneously. The chemical reactions they have developed are spectacular,” said Heiner Linke, Chair of the Nobel Committee for Chemistry.
Kagan, Soai Built on Decades of Research
Kagan made a major breakthrough in 1986 when he developed a method that could influence the outcome of chemical reactions and produce a significantly higher proportion of one molecular mirror image.
Soai later built on this work. In 1995, he demonstrated a remarkable chemical reaction capable of developing towards a homochiral state.
His research reached another milestone in 2003, when he reported a reaction that produced only one of two possible mirror-image molecular forms—a phenomenon previously observed primarily in biological systems.
The discoveries opened new possibilities for understanding how molecular asymmetry could arise and become amplified through chemical processes.
Importance for Modern Medicine
The Nobel Academy said the laureates’ work has had a major influence on modern chemistry, particularly in the pharmaceutical industry.
The ability to selectively produce the desired mirror-image form of a molecule can be crucial because different molecular forms may interact differently with biological systems, directly affecting the effectiveness of medicines.
About the Nobel Laureates
Henri B. Kagan, born in 1930 in Boulogne-Billancourt, France, received his PhD from the Collège de France in 1960. He is Professor Emeritus at the former Université Paris-Sud.
Kenso Soai, born in 1950 in Hiroshima, Japan, earned his PhD from the University of Tokyo in 1979 and is Professor Emeritus at Tokyo University of Science.
Their combined discoveries have helped transform scientists’ understanding of asymmetric chemical reactions and provided important insights into one of chemistry’s most enduring questions: how nature came to favour one molecular mirror image over the other.
