Recognition for asymmetric synthesis
Henri B. Kagan and Kenso Soai have been awarded the 2026 Nobel Prize in Chemistry for discoveries involving non-linear effects and autocatalysis in asymmetric organic synthesis. The Royal Swedish Academy of Sciences said on October 7 that their work helped explain how chemical systems can develop a strong preference for one of two mirror-image forms.
Many molecules can exist as two structures that mirror one another, a property known as chirality. Biological chemistry is strikingly selective: proteins, for example, use amino acids with one handedness even though their mirror variants are chemically possible. Reactions carried out without an asymmetric influence had typically produced equal amounts of both forms, leaving chemists with the challenge of understanding and controlling how one could dominate.
That control is also practical. When chemists design molecules that interact with living systems, including medicines, two mirrored forms may not produce the same biological effect. Methods that favor the intended form can therefore be central to efficient and selective synthesis.
Two steps toward homochirality
The Academy credits Kagan with a decisive advance in 1986. His work demonstrated a non-linear effect in an asymmetric reaction, enabling a larger excess of one mirror form than researchers had expected from the composition of the chiral influence used in the process. The finding changed how chemists understood amplification in asymmetric synthesis.
Soai then developed a reaction in which the product helps catalyze its own formation. A key publication appeared in 1995, and the Academy says that in 2003 he demonstrated a reaction yielding only one of the two possible mirror forms. The result supplied a chemical model for how a small initial imbalance could reinforce itself until a system became homochiral, without invoking biology as the mechanism.
Nobel Committee for Chemistry chair Heiner Linke described the laureates' contribution as a solution to the longstanding question of how homochirality can arise spontaneously. The Academy also highlighted the influence of their discoveries on chemists designing reactions used to manufacture pharmaceuticals.
Kagan was born in 1930 in Boulogne-Billancourt, France, earned his doctorate from the Collège de France in 1960 and is professor emeritus at the former Université Paris-Sud. Soai was born in Hiroshima in 1950, completed his doctorate at the University of Tokyo in 1979 and is professor emeritus at Tokyo University of Science.
The laureates will divide the prize of 12 million Swedish kronor equally. Their recognition connects a fundamental question about life's molecular handedness with techniques that allow synthetic chemistry to select and amplify a desired molecular form.
