Portraits of Henri Kagan and Kenso Soai are shown on the screen as they are awarded the 2026 Nobel Prize in Chemistry, at the Royal Swedish Academy of Sciences in Stockholm, Sweden, Wednesday.Fredrik Sandberg/The Associated Press
Two scientists who studied the properties and production of molecules that are mirror images of one another have been awarded the 2026 Nobel Prize in Chemistry.
On Wednesday, members of the Royal Swedish Academy of Sciences announced that Henri Kagan of Université Paris-Sud, Orsay, and Kenso Soai of the Tokyo University of Science will share this year’s chemistry Nobel.
Both made key contributions to the understanding of “chirality,” a property that means some molecules can have left- and right-handed versions.
Their discoveries have proved important for the development of pharmaceuticals, many of which require the production of only one version of a molecule and not its mirror twin.
For example, in some cases, the mirror version of a molecule is not only ineffective but harmful. When the drug thalidomide was marketed as a morning sickness pill starting in the 1950s, the consequences were tragic: The mirror image of the active drug turned out to cause severe birth defects.
“How can a reaction be designed to spontaneously create only one of the two mirror images without involving any other chiral molecule? It is this puzzle that this year’s laureates have solved,” Heiner Linke, chair of the Nobel Committee for Chemistry, said during Wednesday’s announcement.
The work also helps to illuminate why life on Earth is based only on left-handed versions of certain key organic molecules.
Dr. Kagan was born in 1930 in Boulogne-Billancourt, France, and received his PhD from the College of France in Paris in 1960.
Through the 1970s and 80s he developed reactions in which catalysts enhanced the production of one version of a mirror molecule relative to the other.
The work was recognized as a breakthrough for its practical applications, including for the development of flavour and scents, in which only one version of a chiral molecule can be sensed.
Dr. Kagan was awarded the prestigious Wolf Prize in Chemistry 2001. Now 95, he is among the oldest winners of a chemistry Nobel.
Japanese Nobel laureate Kenso Soai receives flowers as he arrives for a press conference after winning the Nobel Prize in Chemistry at the Tokyo University of Science, Wednesday.ANDREW CABALLERO-REYNOLDS/AFP/Getty Images
Dr. Soai was born in 1950 in Hiroshima, Japan, and received his PhD from the University of Tokyo in 1979.
In the 1990s, he discovered a chiral substance known as 5-pyrimidyl alkanol, which acts as an autocatalyst, a molecule that can create itself.
By 2003, he had developed a chemical reaction in which chiral molecules formed from non-chiral precursors. He then showed how a very small excess of one version of the mirror molecule would eventually grow in proportion to take over the reaction, until it was the sole version remaining.
Apart from the origin of life more than four billion years ago, which produced a biology with exclusively left-handed chemistry, no other such examples are currently known.
At Wednesday’s announcement, Peter Somfai, a member of the Nobel Committee, said Dr. Soai’s discovery is “probably the coolest experiment in organic chemistry.”
Each year the Chemistry prize marks the third in a series of Nobel Prize announcements.
On Monday, Karl Deisseroth, Peter Hegemann and Georg Nagel were awarded the Nobel Prize in physiology or medicine for creating the field of optogenetics, a method of genetically modifying neurons to react to light that has transformed brain research.
On Tuesday, Francis Halzen, who leads a giant neutrino detection experiment in Antarctica, was named this year’s winner of the Nobel Prize in physics.
Recipients of the Nobel Prize in literature and the Nobel Peace Prize are scheduled to be announced on Thursday and Friday, respectively. The winner of this year’s Nobel Memorial Prize in Economic Sciences will be announced on Oct. 12.