Stephen Buchwald (Indiana, United States; 1955) is Associate Head of the Department of Chemistry and, since 1997, Camille Dreyfus Professor at Massachusetts Institute of Technology. It was at MIT precisely where he began his academic career in 1984, rising to a professorship in 1993.
Buchwald received his Bsc in Chemistry from Brown University then went on to earn his PhD from Harvard University in 1982. His thesis work, with Jeremy R. Knowles, concerned the mechanism of phosphoryl transfer reactions in chemistry and biochemistry and as a postdoctoral fellow at California Institute of Technology (Caltech) he continued to work on basic research lines.
He is co-author of more than 420 published papers and has 44 patents to his name. In 1999-2009, he was the world’s most highly cited chemist with an h-index of 123.
Buchwald is a member of the American Academy of Arts and Sciences and the U.S. National Academy of Sciences. His multiple distinctions include the Award for Creative Work in Synthetic Organic Chemistry and Award in Organometallic Chemistry, both from the American Chemical Society, the Linus Pauling Medal, and a MERIT award from the U.S. National Institutes of Health.
Speech
Basic Sciences 7th edition
Behind many technological breakthroughs there stands a new chemical bond. In the last ten years, for instance, the pharmaceuticals industry has been able to raise the pace of drug synthesis many times over thanks to the discovery of a more efficient way to form carbon-nitrogen bonds. The author of this discovery and winner in the seventh edition of the Frontiers of Knowledge Awards in the Basic Sciences category is the U.S. chemist Stephen Buchwald.
The chemistry we owe to Buchwald, a professor at Massachusetts Institute of Technology (MIT), has had “great impact” on the “efficient synthesis of modern pharmaceuticals and compounds for agricultural use,” in the words of the award citation, and “has been applied to the creation of drugs for numerous diseases.”
Atoms join together to form molecules, which form macromolecules, which form compounds… like an invisible, universal model construction game. The game, however, has strict rules for deciding which atoms and molecules react, and under what conditions, so creating new pieces is a formidable task. And this, metaphorically, is what the new laureate has accomplished.
Stephen L. Buchwald has enlarged the chemical universe by constructing catalysts that form carbon-nitrogen and carbon-carbon atomic bonds. These bonds, particularly carbon-nitrogen, play a key role in drug development so are eagerly sought after by the pharmaceuticals industry. However, until Buchwald’s breakthrough there were no catalysts able to generate them on a systematic basis.
Catalysts are compounds that facilitate a given reaction. The carbon and nitrogen atoms present in organic molecules tend not to interact, yet each one binds easily to the catalyst. One of the characteristics of this compound is, accordingly, proximity, since carbon and nitrogen atoms binding to the same catalyst molecule are held more closely together, but the catalyst also provides the right electronic properties for the desired carbon-nitrogen bond to form. Once these conditions are fulfilled, the catalyst is regenerated and becomes available for further use, meaning the catalytic cycle can be re-run billions of times over.
The type of catalyst employed in carbon-nitrogen and carbon-carbon bonds — among many others — consists of a metal center and a molecule known as a ligand. It is in this last element that Buchwald made his groundbreaking contribution. The Buchwald ligand — actually a whole family of ligands of similar structure — is highly active and also air-stable, making it infinitely easier to handle. It is these qualities that have enabled the resulting catalysts, and therefore carbon-carbon and carbon-nitrogen reactions, to be used on an industrial scale.
A token of the importance of this achievement is that between 1999 and 2009 Buchwald had the highest number of citations per paper of any chemist in the world.
Despite the immense practical utility of his work, Buchwald’s research interest is by no means confined to the applied side. Experience, he says, has taught him that “chemistry has applications in the most diverse areas, from medicine to materials, and if you’re successful the impact can resonate far and wide.”
“Chemistry has applications in the most diverse areas, from medicine to materials, and if you’re successful the impact can resonate far and wide.”
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He looks at the science “from both a practical and fundamental standpoint” and is equally absorbed by both. In fact he began his career in basic research, and likes to maintain a feedback loop in his lab team between fundamental and applied work.
Chemistry for Buchwald is above all ‘a challenge’ that he fell in love with at a young age: “I had this fantastic chemistry teacher in high school, young and dynamic, who infected me with his enthusiasm. Then I had the chance to spend a summer doing research before university, and that’s when I fell in love. With chemistry and with the people involved, because you meet a lot of really interesting types.”
Stephen Buchwald completed a degree in chemistry at Brown University then went on to earn a PhD from Harvard in 1982. Two years later, after a postdoctoral stay at the California Institute of Technology (Caltech), he joined the faculty at MIT. It was not until 1993 that he initiated a line of work with a more applied focus, exploring the formation of carbon-nitrogen bonds.
The source of the change was the interest shown by the pharmaceutical industry in one of his basic outcomes: “They explained to me how pressing the need was [to be able to form carbon-nitrogen bonds], so we understood that this was something major, and put a growing effort into the project.”
In this competitive field, he credits the members of his group with contributing to a house method where each idea is experimentally tested and modified in consequence until arriving at the ‘optimal system’. It was this procedure that led him to the ligand class that bears his name: “The original idea for its structure resulted from using a combination of empiricism and intuition to overcome deficiencies in our previously employed ligands,” he relates.
His latest work probes deeper into the possibilities of the chemical universe, in the shape of carbon-fluorine and carbon-trifluoromethyl bonds. The adventure continues.
