Kagan and Soai Win Chemistry Nobel

French chemist Henri B. Kagan and Japanese chemist Kenso Soai have won the 2026 Nobel Prize in Chemistry for discovering nonlinear effects and autocatalysis in asymmetric organic synthesis. Their work explains how a chemical reaction can produce one molecular mirror image in overwhelming excess over the other.

The Royal Swedish Academy of Sciences announced the laureates at a press conference in Stockholm at 11:45 a.m. CEST on Wednesday, October 7, corresponding to 3:45 p.m. Bangladesh time. The Academy said their discoveries provide an important solution to a long-standing question in chemistry: how molecular asymmetry can arise spontaneously.

Many molecules exist in two forms that are mirror images of each other. This property is known as chirality, while the two mirror-image molecules are called enantiomers. Although they contain the same atoms and chemical bonds, their three-dimensional arrangements differ.

That distinction can be crucial in living systems. Two molecular mirror images can interact differently with biological systems. One may produce a desired effect, while its mirror image may behave differently. This makes the controlled production of a specific molecular form particularly important in pharmaceutical chemistry.

A major breakthrough came from Henri Kagan in 1986. He demonstrated that a small difference in the ratio of two chiral forms of a catalyst could generate a much larger difference in the molecular products. This phenomenon became known as a nonlinear effect.

Kenso Soai then pursued a more remarkable possibility: a chemical product that could accelerate the formation of more of itself. In 1995, he developed a key reaction with the potential to become homochiral through autocatalysis.

In 2003, Soai demonstrated an even more striking reaction. Starting without a chiral molecule, a tiny random imbalance could give one molecular form a slight advantage. That form then accelerated its own production, allowing the initial imbalance to grow dramatically. The reaction could ultimately produce almost exclusively one mirror-image form.

Their work has helped chemists understand how homochirality—the dominance of one molecular handedness—can emerge. This is also relevant to one of the major questions surrounding the origin of life: whether an early chemical process could have amplified a tiny molecular imbalance into the strong asymmetry seen in biological chemistry.

The practical significance extends beyond fundamental science. The principles developed by Kagan and Soai are important for designing chemical reactions that selectively produce desired molecular forms, including compounds relevant to pharmaceutical development.

According to the Royal Swedish Academy of Sciences, Henri B. Kagan was born in 1930 in Boulogne-Billancourt, France. He is professor emeritus at the former Université Paris-Sud. Kenso Soai was born in Hiroshima, Japan, in 1950 and is professor emeritus at Tokyo University of Science.

The 2026 Nobel Prize in Chemistry carries a total award of 12 million Swedish kronor, which will be divided equally between the two laureates.

The Chemistry Nobel follows the 2026 Physics Nobel awarded to Francis Halzen on October 6. Halzen was recognized for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos from astrophysical sources.

//DBTech/PAN/SMP/DPO//