Henri B. Kagan at Paris-Saclay University, and Kenso Soai at the Tokyo University of Science have won this year’s Nobel Prize in Chemistry “for the discovery of non-linear effects and autocatalysis in asymmetric organic synthesis.”
“There are many, many, many excellent researchers in this field. So I’m very especially glad to receive this prize,” Soai said on a phone call during the prize announcement. In 3D, molecules can have multiple possible forms that are mirror images of each other. This property is known as chirality, or handedness because human hands are also mirror images.
Many biological molecules—sugars, proteins, DNA—are made from chiral building blocks. “Life as we know it is homochiral,” Heiner Linke, chair of the Nobel Committee for Chemistry, said during the announcement. Exactly how life arose favoring one chiral form over another remains a mystery, but this year’s laureates’ work has helped shed some light on it.
Aside from fundamental exploration into how the world as we know it was assembled, research in chiral catalysis also has extensive commercial applications. Many pharmaceuticals, for example, have chiral forms. For instance, Novrad (levopropoxyphene) was developed by Eli Lilly & Co. in the 1960s as a cough medicine, while the company developed the mirror-twin molecule, Darvon (dextropropoxyphene), as a pain reliever. Neither of these drugs is on the market today, but being able to make the right mirror-image molecule is crucial to having a chiral drug that works as intended.
Asymmetric organic synthesis is the art of building one chiral form of a molecule over another. Usually this selectivity is accomplished by using a catalyst or additive that is itself chiral to basically mold the reaction product in its image.
Erick M. Carreira, an organic chemist at the Swiss Federal Institute of Technology (ETH), Zurich, says he thinks the prize for the pair is long overdue.
Asymmetric catalysis has been the subject of two previous Nobel Prizes—in 2001 and 2021—but “this year’s prize is about the special phenomena that the laureates discovered,” says Christina Moberg, professor emeritus in organic chemistry at KTH Royal Institute of Technology and a member of the Royal Swedish Academy of Sciences.
In 1986, Kagan published his discovery of nonlinear effects in chiral reactions—meaning that the amount of chirality transferred from catalysts to products is not always one to one. It’s possible to have products that are more chirally enriched than the catalysts, or less. These effects arise because one form of the catalyst is usually more reactive than the other, “and that’s proved incredibly useful in a number of different settings,” according to Carreira.
Around a decade later, Soai developed the first autocatalytic chiral reaction, which creates chiral products from starting materials that are a mixture of both chiral forms. A tiny excess of one enantiomer gets amplified until one form dominates, with the product essentially acting as a chiral template for the starting materials. He demonstrated this approach with the alkylation of a pyrimidine aldehyde with diisopropylzinc, now known as the Soai reaction. “That is just an amazing reaction that he’s worked out,” Carreira says. “And the implications for the origins of chirality on planet Earth, you know, is there and is amazing. It just blows your mind.”
“To be able to selectively make handed molecules is absolutely critical, because life is handed, and the world is handed, and so if you can control the handedness of the therapeutic or the molecular system that you put out there, then that can lead to control of its function and its downstream effects,” says Rigoberto Hernandez, American Chemical Society president (ACS publishes C&EN but is not involved in editorial decisions). Today’s prize, he says, is “a reminder that chirality, or handedness, matters.”
Kagan and Soai will share the 12 million Swedish kronor ($1.2 million) prize.
Bethany Halford, Christopher Gorski, and Laura Howes contributed reporting.
UPDATE:
This story was updated on Oct. 7 2026 to add more information about the winners and quotes from Kenso Soai, Heiner Linke, Erick Carreira, Christina Moberg and Rigoberto Hernandez.
