Nobel Prize in chemistry awarded for 'greener' way to make molecules

Twenty years ago, Benjamin List and David W.C. MacMillan invented a new way to make molecules. It's already dramatically changed the field of chemistry for the better.

Monisha Ravisetti Former Science Writer
Monisha Ravisetti was a science writer at CNET. She covered climate change, space rockets, mathematical puzzles, dinosaur bones, black holes, supernovas, and sometimes, the drama of philosophical thought experiments. Previously, she was a science reporter with a startup publication called The Academic Times, and before that, was an immunology researcher at Weill Cornell Medical Center in New York. She graduated from New York University in 2018 with a B.A. in philosophy, physics and chemistry. When she's not at her desk, she's trying (and failing) to raise her online chess rating. Her favorite movies are Dunkirk and Marcel the Shell with Shoes On.
Monisha Ravisetti
3 min read
Nobel Prize in chemistry: Benjamin List and David W.C. MacMillan

On Wednesday, Benjamin List and David W.C. MacMillan were honored with the Nobel Prize in chemistry for their invention of asymmetric organocatalysis.

Jonathon Nackstrand / Getty Contributor

This year's Nobel Prize in chemistry went to scientists who designed an environmentally friendly and cost-effective way to build highly precise molecules. Since its genesis in the year 2000, their invention has become a staple for creating a wealth of materials integral to our lives. "It's already benefiting humankind, greatly," said Pernilla Wittung Stafshede, a member of the Nobel committee for chemistry.

Benjamin List and David W.C. MacMillan are the scientists behind what she calls an "elegant" tool for molecule construction. It's referred to as asymmetric organocatalysis, and it's absolutely fascinating.

When making a drug, for instance, the variety of molecules that constitute the medication must be 100% accurate. Just one minuscule bond out of place could turn what should've been a pain relief pill into an obsolete packet of powder -- or maybe even something dangerous.

The announcement came early in the day for List, who said it was a moment he'll never forget.  

"I thought someone was making a joke with me," List remarked to the committee on first hearing he won the prize. "I was having breakfast with my wife."

An interesting component of drug construction that medical researchers grapple with has to do with molecules' mirror images. Just like our hands are mirror images of each other, molecules have reflections, too. The difference between the two is often so significant that a left-hand molecule could have a different taste and smell than its right-hand counterpart.

Our bodies can tell the mirror images apart, which means the medications we ingest have to as well.

With that in mind, scientists craft specific chemical reactions to produce the exact type and mirror image of molecules they seek. Such reactions are controlled, started and sped up by items called catalysts. Before the pioneering invention of organocatalysis, everyone thought their options were only metal catalysts or large enzyme catalysts.

While those compounds are effective, they can sometimes be inaccurate in those vital nuances of molecular construction and tend to leave behind too much chemical waste. That's why List and MacMillan's tool changed the game. It introduced a third, novel catalyst to the pool: small organic molecules that don't pose the same issues as metal and enzyme catalysts.

Wittung Stafshede called the trailblazing development a "precise, cheap, fast and environmentally friendly" alternative to metal and enzyme catalysts.

"You're not solving a problem, you're adding something," said member of the committee Peter Somfai. "We have a new tool that we can use when thinking about -- how do we solve this problem?"

"The obvious answers or the obvious solutions are sometimes just too obvious," he continued. "I'm an organic chemist, I'm working with small organic molecules everyday -- but I didn't think of it. ... It was just too obvious."

But even though the discovery was first made in the year 2000, List explained to the committee that it took the full 20 years to home in on the method of asymmetric organocatalysis. That's why, he says, the invention is being recognized now.

"Our early-days catalysts were maybe a million times less efficient," he said, adding that, now, the team's extremely reactive ones "can do stuff that you can't do with enzymes or even the most sophisticated metal complexes that people have developed before."