Nobel Chemistry Prize Recognizes Breakthrough in Molecular Asymmetry

STOCKHOLM (AP) — Henri B. Kagan and Kenso Soai won the Nobel Prize in chemistry Wednesday for their efforts to resolve mysterious mirror images in chemical molecules, a discovery that transformed modern medicine.

Many molecules of life come in versions that look alike but aren’t exactly identical, like right and left hands. One mirror image of the chemical carvone smells like mint, for example, while the other has a whiff of caraway.

When designing drugs to treat diseases, scientists want to be choosy about which mirror image they’re getting. They want the version of a molecule that’ll treat a cold, not the kind that’ll make the sniffles worse.

Kagan and Soai found ways to make chemistry pick a side, designing and manipulating reactions to produce the desired mirror image.

“This is probably the coolest experiment in organic chemistry,” said Peter Somfai, a member of the Nobel Committee for Chemistry. “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.”

Scientists paid tribute to Kagan and Soai’s groundbreaking work, which the Nobel committee described as a feat never previously achieved by anyone “other than life itself.”

“It might be difficult to say that this drug, or that drug, was developed using this,” Somfai said. “I would say all of them, because we use this as a tool, we use this as an understanding, how to develop catalysts, how they function.”

“Chirality” comes from the Greek word for “hand.”

In the 1980s, Kagan’s work showed there might be a way to design reactions to produce one form of a molecule over the other. Years later, Soai brought that dream to life. He created the first-ever chemical reaction to produce only one of a molecule’s mirror images, in what’s now known as the “Soai reaction.”

“The medicines we have today would not be possible without this chemistry,” said Rigoberto Hernandez, president of the American Chemical Society.

Kagan, 95 years old and born in France, is affiliated with the Université Paris-Sud in Orsay, France, and Soai, born in 1950 in Japan, with the Tokyo University of Science.

The French Academy of Sciences, of which Kagan is a member, congratulated the two scientists and expressed its pride in the prize.

Neither the Université Paris-Sud nor the Tokyo University of Science responded immediately to AP requests for comment.

“I’m very excited to receive the very nice news,” Soai told the committee and journalists by phone. “Of course this is one of the most exciting days in my life.”

He said he was shopping near his home when he was reached by the Nobel committee.

The Royal Swedish Academy of Sciences announced the winner in Stockholm.

Last year, three scientists won the chemistry Nobel for their development of new molecular structures that can trap vast quantities of gas inside, laying the groundwork to potentially suck greenhouse gases out of the atmosphere or harvest moisture from desert environments.

This year’s prizes began with the Nobel for medicine, awarded Monday to three scientists whose work led to a tool that uses light to help unravel how the brain works. The physics award Tuesday recognized a scientist’s efforts to demystify a rare group of neutrinos.

The literature prize is set to be awarded Thursday. After Friday’s peace prize is awarded, the Nobel Memorial Prize in Economic Sciences will be announced Monday.

The prize money this year is 12 million Swedish kronor (about $1.2 million), whether for an individual, a small group of laureates or an organization.

This story has been corrected to clarify that Kagan, and not Soai, is 95 years old.

Ramakrishnan reported from New York and Dazio from Berlin. Associated Press journalists Alexa St. John in Detroit and Catherine Gaschka in Paris contributed to this report.

AP Nobel Prizes: https://apnews.com/hub/nobel-prizes