Three scientists share Nobel Prize in chemistry
Two Japanese and an American who developed a key synthetic technique for making complex organic molecules used in medicine, agriculture and electronics have been awarded the 2010 Nobel Prize in chemistry.
Richard Heck, 79, emeritus professor at the University of Delaware, Ei-Ichi Negishi, 75, of Purdue University and Akira Suzuki, 80, a retired professor at Hokkaido University in Sapporo, Japan, will share the $1.5-million award for their creation of a family of reactions involving the metal palladium that allow chemists to link carbon atoms together more efficiently and with less waste.
Carbon atoms are the building blocks of life, the skeletons of organic molecules that play a key role in all the biochemical processes of living things. However, carbon atoms are difficult to link together in precise ways, and the main thrust of organic chemistry for more than 100 years has been finding new ways to join them.
The importance of that effort is illustrated by the fact that this is the fifth Nobel Prize in chemistry awarded for the development of new synthetic techniques to make carbon-carbon bonds.
“Making new bonds in chemistry is not an easy process,” said chemist Joseph S. Francisco, a colleague of Negishi at Purdue and president of the American Chemical Society. “The coupling reactions involving palladium [developed by the award winners] add to the toolbox for chemists in making new kinds of materials. This is a great acknowledgement by the Nobel chemistry committee of the real value and utility of this chemistry.”
The palladium in the new reactions serves both to hold the reacting carbon atoms together in the proper orientation to achieve the desired products and to nudge the reaction gently to completion. As it is a catalyst, Francisco said, “it is used, but never used up.”
Interest in palladium-catalyzed reactions began in the early 1950s when the German chemical company Wacker Chemie AG began using palladium to transform the chemical ethylene into acetaldehyde, a widely used raw material.
Heck, then a researcher at Hercules Corp. in Delaware, was able to improve on the reaction, giving it both greater specificity and wider utility. Among his first feats was joining a short carbon chain to a ring of carbon atoms to produce styrene, the raw material of the now widely used plastic polystyrene.
A similar process is also used in the production of the anti-inflammatory drug naproxen, the asthma drug montelukast and the herbicide prosulfuron.
In the 1970s, Negishi and Suzuki developed variants on the reaction that made it more versatile. Negishi first linked carbon fragments to zinc atoms, which then transferred them to palladium in a more precise and efficient manner. Suzuki did the same thing with boron atoms.
Chemists have since used these reactions to produce substantial quantities of potential medicines that are found in nature in small amounts. One of the most spectacular feats was the 1994 synthesis of a naturally occurring chemical called palytoxin, which was first isolated from a coral in Hawaii in 1971. Palytoxin contains 129 carbon atoms linked in a precise three-dimensional structure that chemists were able to reproduce using the Suzuki reaction.
By some estimates, at least 25% of chemical reactions in the pharmaceutical industry use the methods developed by the three researchers, according to the Nobel committee.
Heck, who received his undergraduate and graduate degrees from UCLA and is now retired and living in the Philippines, seemed shocked by the award. In a news conference organized by the Nobel committee, he said, “It was a big surprise to me.”
At the same conference, Negishi said he had been dreaming of the prize since his youth. “The Nobel Prize became a realistic dream of mine when I was in my 20s,” he said. “I have accomplished maybe half of my goals, and I would definitely like to work for at least a couple more years.”
In a televised news conference in Japan, Suzuki said he was honored by the award and hoped it would inspire young Japanese to pursue chemistry. “A resource-poor country like Japan can only rely on people’s endeavor and knowledge,” he said.