Barry Sharpless

K. Barry Sharpless
Born	Karl Barry Sharpless 4/28/1941
Birthplace	Philadelphia, Pennsylvania, U.S.
Nationality	American
Occupation	Chemist, academic
Title	W. M. Keck Professor of Chemistry
Employer	Scripps Research
Known for	Asymmetric catalysis, click chemistry, Sharpless epoxidation
Education	Dartmouth College (A.B.), Stanford University (Ph.D.)
Awards	Nobel Prize in Chemistry (2001, 2022), Priestley Medal (2019)

Karl Barry Sharpless (born April 28, 1941) is an American chemist at Scripps Research in La Jolla, California. He's made transformative contributions to two major areas of chemistry: asymmetric catalysis and click chemistry. In 2001, he won the Nobel Prize in Chemistry for his work on chirally catalyzed oxidation reactions, sharing it with William S. Knowles and Ryōji Noyori. Then, twenty-one years later in 2022, he received a second Nobel Prize in Chemistry for developing click chemistry. That made him only the fifth person ever to win two Nobel Prizes and just the second, after Frederick Sanger, to win the Nobel Prize in Chemistry twice. Over more than fifty years of work, Sharpless developed several major chemical reactions. The Sharpless epoxidation, the Sharpless asymmetric dihydroxylation, and the copper(I)-catalyzed azide–alkyne cycloaddition transformed how chemists work in organic synthesis, pharmaceutical development, materials science, and chemical biology.

Early Life

Karl Barry Sharpless was born on April 28, 1941, in Philadelphia, Pennsylvania. He grew up in the Philadelphia area, but not with his nose in books. His childhood was outdoors and practical. In his Nobel biographical sketch, he recalled spending most of his early years outside, developing interests that were hands-on and experiential.

From sixth grade through high school, Sharpless attended a Quaker school on the Philadelphia city line. The school held Quaker Meetings twice a week, open to the entire student body. These meetings involved communal silence and reflection. It was the kind of environment that shaped how he thought. Still, by his own account, Sharpless wasn't drawn to academics in any conventional way. His path toward chemistry emerged gradually, not as something predetermined.

His childhood passions were physical and rooted in nature. He spent considerable time fishing, an activity that stayed with him throughout his life. This early engagement with the natural world likely sharpened his observational habits and his comfort with the unexpected. In interviews, Sharpless has talked about how important it is to notice unexpected results in the lab, a disposition that traces back to his formative years exploring outdoors.

Education

Sharpless enrolled at Dartmouth College in Hanover, New Hampshire for his undergraduate studies. He finished in 1963 with his Bachelor of Arts degree. After his two Nobel Prizes, Dartmouth would celebrate him as one of its most notable alumni.

Graduate school came next at Stanford University, where he earned his Ph.D. in chemistry. Stanford's organic chemistry program was at the frontier of the field, and his doctoral training gave him both deep technical knowledge and exposure to cutting-edge research. He then did postdoctoral work before beginning his independent academic career, which would eventually take him through several top chemistry departments in the country.

Career

Early Academic Career and Asymmetric Catalysis

Sharpless started his independent career in the 1970s. His focus was on developing new methods for selective chemical transformations. Oxidation reactions especially interested him. These reactions are fundamental to organic synthesis, but they'd always been tricky when it came to controlling the three-dimensional shape of the products. The real problem was chirality: molecules that exist as mirror images of each other, much like left and right hands. In biology, the difference matters enormously. Pharmaceutical chemists needed ways to selectively make one mirror-image form of a molecule instead of the other, and that capability was crucial.

In the early 1980s, Sharpless and his team achieved something significant. As Scripps Research describes it: "It was 1980 and the experiments were going suspiciously well." They'd developed the Sharpless epoxidation. This reaction uses a titanium catalyst combined with a chiral auxiliary to turn allylic alcohols into epoxides with impressive selectivity. What made it special wasn't just the selectivity. It worked reliably on a wide range of substrates, making it genuinely useful to working chemists instead of just a laboratory novelty.

Then came the Sharpless asymmetric dihydroxylation. This allowed chemists to add two hydroxyl groups to an alkene with tight control over which mirror-image form they got. Together with the Sharpless aminohydroxylation, these reactions formed a toolkit for asymmetric oxidation that chemists in both academia and pharmaceutical industry started using regularly.

The Nobel Prize in Chemistry followed in 2001 "for his work on chirally catalyzed oxidation reactions." He shared the prize with William S. Knowles and Ryōji Noyori, recognized for their contributions to asymmetric catalysis in hydrogenation reactions. In his biographical sketch for the 2001 prize, Sharpless reflected on his career path and what had driven his research.

Move to Scripps Research

Sharpless joined Scripps Research (formerly The Scripps Research Institute) in La Jolla, California as W. M. Keck Professor of Chemistry. The place suited him. It was built for ambitious, curiosity-driven work of exactly the kind he pursued. At Scripps, he kept developing new reactions with broad uses, but his research took a different turn in the late 1990s and early 2000s.

Click Chemistry

By the time he received his first Nobel Prize in 2001, Sharpless was already developing a new approach to chemical synthesis. He called it click chemistry. The concept rests on finding and using chemical reactions that are highly reliable, selective, and easy to perform, reactions that "click" together molecular building blocks as simply as snapping shut a seat belt buckle.

He introduced click chemistry formally in a landmark 2001 paper. He and his collaborators laid out what made a "click" reaction. It needed to be modular, work broadly, give high yields, produce only benign byproducts, and be stereospecific (though not necessarily selective for one mirror-image form). The reaction should work under simple conditions, ideally with readily available starting materials and reagents, and need no solvent or only water.

The most famous click reaction, the one that became almost synonymous with the whole concept, is the copper(I)-catalyzed azide–alkyne cycloaddition or CuAAC. Sharpless developed it independently from the Danish chemist Morten Meldal. The reaction couples an azide with a terminal alkyne in the presence of a copper(I) catalyst to form a 1,2,3-triazole. It's remarkably reliable, works in water, tolerates countless functional groups, and runs at or near room temperature. Those characteristics made it immediately useful across chemistry and beyond.

In his Nobel Lecture for 2022, published in Angewandte Chemie International Edition as "Click Chemistry: The Certainty of Chance," Sharpless described how click chemistry had been shaped by deliberate design and lucky accidents. He noted that "the most important certainty-of-chance outcome of click chemistry was the realization that perfect reactions" could be identified and harnessed for practical purposes.

Applications for click chemistry spread far beyond traditional organic synthesis. In chemical biology, the CuAAC reaction became standard for labeling and tracking biomolecules inside living cells. In materials science, it helped construct polymers and surface modifications. In drug discovery, it allowed rapid assembly and screening of molecular libraries. In bioconjugation, it enabled precise attachment of functional groups to proteins, nucleic acids, and other biomolecules.

Sharpless kept expanding the click chemistry concept beyond CuAAC. He and collaborators explored sulfur(VI) fluoride exchange or SuFEx chemistry, which he proposed as a new generation of click reactions. SuFEx reactions create and exchange bonds to sulfur(VI) fluoride groups and share the same desirable properties: reliability, selectivity, and broad applicability.

Second Nobel Prize (2022)

On October 5, 2022, the Royal Swedish Academy of Sciences announced that Sharpless had won the 2022 Nobel Prize in Chemistry, shared with Morten Meldal and Carolyn Bertozzi, "for the development of click chemistry and bioorthogonal chemistry." The Nobel Committee recognized Sharpless for laying the intellectual and experimental foundations of click chemistry, Meldal for independently developing CuAAC, and Bertozzi for extending click chemistry principles into bioorthogonal chemistry, reactions that can happen inside living organisms without disrupting normal biochemical processes.

Peter Schultz, president and CEO of Scripps Research, noted the award's significance. The institution took pride in Sharpless's achievement as a reflection of how deep and influential his research program had been. At Dartmouth, his undergraduate alma mater, the announcement was met with recognition of his lasting connection to the college. The institution noted that the award celebrated "click chemistry," the name Sharpless had coined.

The 2022 Nobel made Sharpless the fifth person in history to win two Nobel Prizes, joining Marie Curie, Linus Pauling, John Bardeen, and Frederick Sanger. He became the second person, after Sanger, to win two Nobel Prizes in Chemistry specifically.

During Nobel Week in Stockholm in December 2022, Sharpless participated in interviews about his career, his philosophy of research, and the development of click chemistry.

Personal Life

Fishing has been known as Sharpless's great passion, a habit that started in childhood near Philadelphia. He's mentioned it in interviews and biographical pieces as one of his most enduring personal pursuits, a counterbalance to the demands of laboratory research.

In 2018, Sharpless suffered a stroke that affected his speech. Despite this serious health setback, he remained engaged with his research and colleagues at Scripps Research. His appearance at the 2022 Nobel ceremony in Stockholm, after his recovery, caught the attention of observers and colleagues.

Colleagues and institutional profiles describe Sharpless as someone who combines intuition, persistence, and a willingness to chase unexpected leads. His career shows long stretches of focused work on specific problems, punctuated by moments when new opportunities or observations prompted a shift in direction.

Recognition

Over his career, Sharpless has received numerous awards and honors reflecting the breadth and depth of his contributions to chemistry.

The two Nobel Prizes in Chemistry come first. In 2001, he received the prize for work on chirally catalyzed oxidation reactions. In 2022, the recognition went to his development of click chemistry.

In 2019, Sharpless won the Priestley Medal, the highest honor the American Chemical Society gives. It recognized his cumulative contributions to chemistry, spanning both asymmetric catalysis and click chemistry. An article in Chemical & Engineering News announcing the award called him "a master at getting molecules to do his bidding" and noted that he'd "pioneered two influential areas of chemistry: asymmetric catalysis and click chemistry." The same article mentioned that when Sharpless won his 2001 Nobel Prize, he'd written in his biographical sketch about the motivations and arc of his career, showing real awareness of his own scientific journey.

Dartmouth College has recognized Sharpless as one of its most distinguished alumni. After the 2022 Nobel announcement, the college published an article celebrating his connection to the institution and his accomplishments.

Legacy

The impact of Sharpless's work on chemistry shows up in multiple ways. The asymmetric oxidation reactions he developed, particularly the Sharpless epoxidation and the Sharpless asymmetric dihydroxylation, became standard tools for synthetic chemists within years of their publication. They made it possible to efficiently produce single-enantiomer compounds. As pharmaceutical regulations increasingly demanded that companies separately evaluate each mirror-image form of chiral drug candidates, this capability became essential. The practical reliability of Sharpless's reactions, which worked across broad substrate ranges with predictable selectivity, was what made them get adopted so widely.

Click chemistry has had an even broader reach, extending well beyond traditional organic synthesis. The CuAAC reaction and related click reactions became routine tools in chemical biology, polymer science, and nanotechnology. The click chemistry concept itself shifted how chemists think about putting molecules together, emphasizing modularity, reliability, and the ability to tolerate many functional groups over the elegance or complexity of the route. This philosophical shift, articulated by Sharpless in his foundational publications, shaped how a generation of chemists approached their work.

The fact that Sharpless produced two separately Nobel-winning bodies of work, developed decades apart, stands out. His trajectory shows that sustained creativity and reinvention are possible within a single scientific career. Rather than refining asymmetric catalysis further, which was already bringing him recognition, Sharpless pursued an entirely new research direction. It required him to articulate a fundamentally different set of values about what makes a chemical reaction useful. Both programs succeeded spectacularly. That success reflects his approach to research: deep chemical intuition combined with a willingness to follow unexpected experimental results wherever they led.

At Scripps Research, Sharpless's legacy lives in the institutional culture and ongoing research programs that build on his work. His contributions remain central to the institute's identity as a leader in chemical research.