Dennis P. Curran | |
---|---|
Born | |
Nationality | American |
Known for | Organic synthesis Radical chemistry Fluorous chemistry |
Awards | Chaire Blaise Pascal Award (2006) [1] Fellow of the American Chemical Society (inaugural class, 2009) [2] Ernest Guenther Award (2015) |
Scientific career | |
Fields | Chemistry |
Institutions | University of Pittsburgh |
Dennis P. Curran (born June 10, 1953) is an American organic chemist and a professor of chemistry at University of Pittsburgh known for his research in the fields of organic chemistry, radical chemistry, and fluorous chemistry.
Curran received his BS degree from Boston College in 1975 and his PhD degree from the University of Rochester in 1979 working under the direction of Andrew S. Kende. After postdoctoral studies with Barry Trost at the University of Wisconsin, he joined the University of Pittsburgh Department of Chemistry as an Assistant Professor in 1981. He became Associate Professor in 1986, Full Professor in 1988, and Distinguished Service Professor in 1995. He became the first Bayer Professor of Chemistry in 1996 and since 2019 is the Covestro Professor of Chemistry.
Chemistry runs in Curran's family. His father, Dr. William V. Curran (1929-2019), was a 60-year member of the American Chemical Society and the inventor of the third-generation cephalosporin antibiotic cefuzonam. His younger brother Kevin J. Curran has won the Technical Achievement Award of the American Chemical Society Division of Organic Chemistry (2007). [3]
Curran is known for his pioneering work on organic radicals and radical cyclizations, especially directed towards organic synthesis. Prior to the 1980s, radicals were neglected because they were thought to be too reactive and too unselective for use in organic synthesis. Curran parlayed cascade reactions of radicals (also called tandem reactions or domino reactions) into powerful tools to make natural products. His 1985 total synthesis of hirsutene, [4] [5] the first of many such syntheses with cascade radical reactions, is today regarded as a classic. [6]
Curran also revitalized atom transfer radical reactions. These reactions are also called Kharasch addition reactions (or sometimes Curran-Kharasch reactions). Morris S. Kharasch discovered and pioneered halogen atom transfer addition reactions in an initial flowering period in the late 1940s and 1950s. About 40 years later, Curran described fast new reactions involving iodine transfer, bromine transfer and functional group transfer, and encompassing radical addition (ATRA), cyclization (ATRC) and annulation. He introduced sunlamps as convenient tools for photo-initiation of ATRA and ATRC reactions. [7] Curran is also a pioneer in stereoselective radical reactions and radical translocation reactions.
Radical reactions are today regarded as powerful tools for synthesis of natural products and other organic molecules. [8] Curran's work helped to expose many of the features that are now considered hallmarks of organic radical reactions. Synthetic economy is a primary attraction. Protecting groups and activating functional groups are often superfluous (atom economy). In addition, several bonds can be formed simultaneously (step/pot economy). Other features include reliability, predictability, selectivity, functional group tolerance and inertness to water and other protic solvents. A 1991 synthesis of the important anti-cancer agent camptothecin illustrates many of these features. The synthesis takes place over six steps centered on a cascade radical reaction that makes three bonds and two rings. There are no protecting groups, no functional group transformations, no reductions and only one oxidation. [9]
Curran has also pioneered many aspects of the relatively young field of fluorous chemistry. Expanding on the initial 1995 concept of fluorous biphasic catalysis, [10] he introduced the concepts of fluorous tagging and fluorous synthesis in 1997 [11] under the new guise of strategy level separations. [12] Curran introduced light fluorous reactions, fluorous triphasic reactions, fluorous phase vanishing reactions (with Ilhyong Ryu) and fluorous mixture synthesis (or FMS). FMS is the first example of solution phase synthesis with separation tagging, [13] and it has been used to make many analogs and stereoisomers of complex natural products. The techniques of FMS allow 4–16 analogs or isomers to be made in a single synthesis. Curran also introduced fluorous solid phase extraction, a simple separation technique that enabled much subsequent work. The high resolution version of the technique, fluorous chromatography, is the basis of FMS.
Curran has held various positions in the American Chemical Society (ACS) Division of Organic Chemistry hierarchy, culminating as Chair of the Division in 2000. He was an Associate Editor of Organic Reactions from 1991–2001 and Editor of Tetrahedron Letters from 1995–2001. He is a member of Organic Syntheses, Inc and edited Volume 83 in 2006. He was a member of the Executive Committee of the symposium "Gomberg•2000, A Century of Radical Chemistry", [14] and he spearheaded the presentation on June 25, 2000, of an ACS National Chemical Landmark to the University of Michigan for Gomberg's 1900 discovery of organic free radicals. [15]
Curran is an ACS Fellow and has received several local ACS Section Awards. His national ACS Awards are: the Cope Scholar Award, [16] under-35 category (now called early-career category) (1988), the Award for Creativity in Organic Synthesis (2000), [17] the Award for Creative Work in Fluorine Chemistry (2008), [18] and the Ernst Guenther Award in the Chemistry of Natural Products (2014). [19] He won the Dr. Paul Janssen Prize for Creativity in Organic Synthesis in 1998. [20] Curran has a long history of interaction with the French organic chemistry community. His awards from France include a Chaire Blaise Pascal (2006) from the Région Île-de-France, and a Doctorat Honoris Causa (honorary doctoral degree) from the Université Pierre et Marie Curie, Paris (2010). [21]
In organic chemistry, allenes are organic compounds in which one carbon atom has double bonds with each of its two adjacent carbon atoms. Allenes are classified as cumulated dienes. The parent compound of this class is propadiene, which is itself also called allene. An group of the structure R2C=C=CR− is called allenyl, where R is H or some alkyl group. Compounds with an allene-type structure but with more than three carbon atoms are members of a larger class of compounds called cumulenes with X=C=Y bonding.
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions. In organic synthesis, organic reactions are used in the construction of new organic molecules. The production of many man-made chemicals such as drugs, plastics, food additives, fabrics depend on organic reactions.
In organic chemistry, Markovnikov's rule or Markownikoff's rule describes the outcome of some addition reactions. The rule was formulated by Russian chemist Vladimir Markovnikov in 1870.
In organic chemistry, the Ugi reaction is a multi-component reaction involving a ketone or aldehyde, an amine, an isocyanide and a carboxylic acid to form a bis-amide. The reaction is named after Ivar Karl Ugi, who first reported this reaction in 1959.
A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom [−Si(CH3)3], which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications.
A transition metal carbene complex is an organometallic compound featuring a divalent organic ligand. The divalent organic ligand coordinated to the metal center is called a carbene. Carbene complexes for almost all transition metals have been reported. Many methods for synthesizing them and reactions utilizing them have been reported. The term carbene ligand is a formalism since many are not derived from carbenes and almost none exhibit the reactivity characteristic of carbenes. Described often as M=CR2, they represent a class of organic ligands intermediate between alkyls (−CR3) and carbynes (≡CR). They feature in some catalytic reactions, especially alkene metathesis, and are of value in the preparation of some fine chemicals.
Moses Gomberg was a chemistry professor at the University of Michigan. He was elected to the National Academy of Sciences and the American Philosophical Society, and served as president of the American Chemical Society.
Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents.
Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes. Research in this field is driven by the need to functionalize fullerenes and tune their properties. For example, fullerene is notoriously insoluble and adding a suitable group can enhance solubility. By adding a polymerizable group, a fullerene polymer can be obtained. Functionalized fullerenes are divided into two classes: exohedral fullerenes with substituents outside the cage and endohedral fullerenes with trapped molecules inside the cage.
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes.
Fluorous chemistry involves the use of perfluorinated compounds or perfluorinated substituents to facilitate recovery of a catalyst or reaction product. Perfluorinated groups impart unique physical properties including high solubility in perfluorinated solvents. This property can be useful in organic synthesis and separation methods such as solid phase extraction. In practice, a perfluorinated alkyl group is incorporated into an otherwise conventional organic reagent as an affinity tag. These reagents can then be separated from organic solvents by extraction with fluorinated solvents such as perfluorohexane.
The Kharasch addition is an organic reaction and a metal-catalysed free radical addition of CXCl3 compounds (X = Cl, Br, H) to alkenes. The reaction is used to append trichloromethyl or dichloromethyl groups to terminal alkenes. The method has attracted considerable interest, but it is of limited value because of narrow substrate scope and demanding conditions.
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Peter Wipf is a distinguished university professor of chemistry at the University of Pittsburgh. His research interests focus on the total synthesis of natural products, the discovery of new transformations of strained molecules, and the development of new pharmaceuticals. He is a Fellow of the Royal Society of Chemistry (RSC), the American Association for the Advancement of Science (AAAS), and the American Chemical Society (ACS).
Michael J. Krische is an American chemist and Robert A. Welch Chair in Science at the Department of Chemistry, University of Texas at Austin. Krische has pioneered a broad, new family of catalytic C-C bond formations that occur through the addition or redistribution of hydrogen. These processes merge the characteristics of catalytic hydrogenation and carbonyl addition, contributing to a departure from the use of stoichiometric organometallic reagents in chemical synthesis.
Edwin Vedejs was a Latvian-American professor of chemistry. In 1967, he joined the organic chemistry faculty at University of Wisconsin. He rose through the ranks during his 32 years at Wisconsin being named Helfaer Professor (1991–1996) and Robert M. Bock Professor (1997–1998). In 1999, he moved to the University of Michigan and served as the Moses Gomberg Collegiate Professor of Chemistry for the final 13 years of his tenure. He was elected a fellow of the American Chemical Society in 2011. After his retirement in 2011, the University of Michigan established the Edwin Vedejs Collegiate Professor of Chemistry Chair. Vedejs died on December 2, 2017, in Madison, Wisconsin.
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