The Nobel Prize in Chemistry 2026 has been awarded to Henri B. Kagan and Kenso Soai for their work on understanding the nature of molecular chirality.
Some molecules - such as amino acids - exist as two variants that are each other’s mirror image, but living organisms only contain one version. How chemical asymmetry such as this – known as homochirality - could have emerged was long a mystery to chemists, but through their research Kagan and Soai discovered a solution to this puzzle, said the Royal Swedish Academy of Sciences - awarding them the Nobel Prize “for the discovery of non-linear effects and autocatalysis in asymmetric organic synthesis”.
“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,” says Heiner Linke, chair of the Nobel Committee for Chemistry.
When chemists they began to experiment with chemical reactions that can form two mirrored molecules, they always obtained equal proportions of both. But chemists often want to produce only one of these mirror images, for example for pharmaceuticals where only one version will have the desired effect.
In awarding the Nobel Prize, the Royal Swedish Academy of Sciences said that Kagan took the first “decisive step” in 1986, when he discovered a new way of manipulating chemical reactions, which allowed him to create a greater excess of one of the mirror images than had previously been thought possible. In 1995 a key publication by Soai took the next step, describes how he designed the first ever chemical reaction that had the potential to be homochiral. In 2003, he finally succeeded. He presented a reaction in which only one of the two possible mirror images was formed.
“Thanks to Henri Kagan and Kenso Soai, we now know how homochirality can emerge. Their discoveries have been decisive for chemists who design reactions for the manufacture of pharmaceuticals,” the Royal Swedish Academy of Sciences said.
“This year’s prize is about foundational chemistry,” said Linke. “Many molecules occur in two different versions. Like my hands, they are one another’s mirror image - they look alike - but they are not identical.” Such molecules are called chiral after the Greek word for hand.
Mirror image forms of the same molecule can have different effects – for example the molecule carvone has two mirror image forms; the right enantiomers smells of spearmint while the its mirror image gives caraway seeds their smell.
We perceive the two in two different ways because we are built of chiral building blocks, Linke said. All the proteins in our bodies are made up of left-handed amino acids while the right-handed versions rarely occur in nature: “So life has we know it is homchiral.”
Enantiomers of chiral drugs can have different effects – the left hand enantiomers of one molecule is the cough medicine Novrad while the right is the painkiller Darvon, said Peter Somfai, member of the Nobel Committee for Chemistry.
Soai showed by his experiments it was possible to create a chirality imbalance and to obtain enantiomers pure product, Somfai said. “You have to be aware, this is probably the coolest experiment in organic chemist,” he said.
“Taken together the groundbreaking discoveries by Henri Kagan and Kenso Soai have reshaped our understanding of molecular chirality, how it is created, amplified and transmitted,” he said.
The Nobel Prize in Chemistry has been awarded 118 times to 202 Nobel Prize laureates between 1901 and 2026; a total of 200 individuals have received the Nobel Prize in Chemistry, and two have won it twice.
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