This year's Nobel Prize in Chemistry has been won by three researchers who pioneered the understanding and use of a very general class of reactions that aid the construction of carbon-based (organic) molecules.

Yves Chauvin of the French Petroleum Institute in Rueil-Malmaison showed how these ‘metathesis’ reactions, long familiar to the petrochemicals industry, actually work.

This understanding helped Richard Schrock at the Massachusetts Institute of Technology (MIT) in Cambridge and Robert Grubbs of the California Institute of Technology, Pasadena, to develop catalysts that made metathesis more controllable and reliable.

Thanks to the trio's work, metathesis is now widely used in the synthesis of many organic compounds, from plastics and pharmaceuticals to herbicides. “It has fundamentally transformed the way chemists think about building new molecules,” says Gregory Fu at MIT, who was a postdoc with Grubbs.

The award “is what we've all been waiting for”, says Steven Ley, an organic chemist at the University of Cambridge, UK. “The work is spectacularly useful and important — it is the chemistry discovery of the past 30 years.”

Metathesis has taken a route — not unusual in chemistry — from industry to the academic laboratory and then back out to industry. In the process, it has been transformed from a curious observation to a useful piece of science.

Robert Grubbs (left), Richard Schrock (top) and Yves Chauvin transformed metathesis from a curiosity to a key chemical tool. Credit: AP PHOTO/J. MCCOOMBE

“People knew there was this funny reaction in petroleum refining,” says John Brown, an organic chemist at the University of Oxford, UK. “Chauvin came up with the first serious mechanism that turned it into rational design. But it was still just a party piece until Schrock came along.”

Metathesis involves two molecules that each contain a double bond between carbon atoms — the bond acts rather like a double handclasp between a pair of dancers. During the reaction, which requires a catalyst containing metal atoms, the molecules effectively exchange partners (metathesis means ‘changing places’). “The molecules are cut in half and put back together again,” says Brown.

In 1971, Chauvin showed how the metal-atom catalyst coordinates this rearrangement. Soon after, Schrock began to look for more effective catalysts and, by 1990, had found that compounds containing molybdenum and tungsten were especially efficient.

But Schrock's catalysts still tended to react with other molecular groups attached to the double bonds. In 1992, Grubbs discovered that ruthenium compounds interfered less with other groups, and were more stable in air. “That really rocketed the reaction into common usage,” says Ley.

“The availability of these improved catalysts has revolutionized organic synthesis,” he adds. “I don't think there is a single organic chemist who hasn't used metathesis.”

The award is a reminder that, in chemistry, the best contributions are often not discoveries, but tools. A general way of making new molecules can find many different applications. “Most people have these catalysts on their shelves,” says Fu.