James L. Leighton

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James Lincoln Leighton (born February 12, 1964, New Haven, CT) is a Professor of Chemistry in the Department of Chemistry at Columbia University. He is known for his non-aldol approaches to polyketides.

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As an undergraduate at Yale University (B.S. 1987), Leighton worked for synthetic chemist Samuel J. Danishefsky. After 2 years with Merck Research Laboratories, Leighton began his graduate studies with Abbott and James Lawrence Professor David A. Evans at Harvard University (Ph.D. 1994), culminating in the total syntheses of both Calyculin A [1] and Zaragozic acid. [2] Leighton continued his chemical studies as an NSF postdoctoral fellow with Sheldon Emery Professor Eric N. Jacobsen, also of Harvard University, developing initial methods for what became known as the Jacobsen hydrolytic kinetic resolution.

In 1996, Leighton began his independent career at Columbia, becoming Full Professor in 2004. In recognition of his scholarly contributions in the laboratory and classroom, he was awarded the Arthur C. Cope Scholar award (2003) by the American Chemical Society, [3] as well as the Mark Van Doren Award for Teaching, Columbia's most prestigious teaching award. [4]

Notable contributions

In addition to Leighton's novel methods for synthesizing natural products, including: CP-263,114, [5] Leucascandrolide A, [6] Mycoticin A, [7] SCH 351448, Dolabelide D, [8] Manzacidin C, Zincophorin, he has also pioneered the concept of strain-release silane Lewis acids. [9] In particular, he has developed a silicon/pseudoephedrine allylation reagent for the highly enantioselective allylation of aldehydes and aldehyde/ketone derived hydrazones to give chiral alcohols and secondary/tertiary carbinamines, respectively.

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Allyl group

An allyl group is a substituent with the structural formula H2C=CH−CH2R, where R is the rest of the molecule. It consists of a methylene bridge (−CH2−) attached to a vinyl group (−CH=CH2). The name is derived from the Latin word for garlic, Allium sativum. In 1844, Theodor Wertheim isolated an allyl derivative from garlic oil and named it "Schwefelallyl". The term allyl applies to many compounds related to H2C=CH−CH2, some of which are of practical or of everyday importance, for example, allyl chloride.

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Asymmetric induction

In stereochemistry, asymmetric induction describes the preferential formation in a chemical reaction of one enantiomer or diastereoisomer over the other as a result of the influence of a chiral feature present in the substrate, reagent, catalyst or environment. Asymmetric induction is a key element in asymmetric synthesis.

Schwartzs reagent Chemical compound

Schwartz's reagent is the common name for the organozirconium compound with the formula (C5H5)2ZrHCl, sometimes called zirconocene hydrochloride or zirconocene chloride hydride, and is named after Jeffrey Schwartz, a chemistry professor at Princeton University. This metallocene is used in organic synthesis for various transformations of alkenes and alkynes.

Schmidt reaction

The Schmidt reaction is an organic reaction in which an azide reacts with a carbonyl derivative, usually a aldehyde, ketone, or carboxylic acid, under acidic conditions to give an amine or amide, with expulsion of nitrogen. It is named after Karl Friedrich Schmidt (1887–1971), who first reported it in 1924 by successfully converting benzophenone and hydrazoic acid to benzanilide. Surprisingly, the intramolecular reaction was not reported until 1991 but has become important in the synthesis of natural products.

The Meyers synthesis is an organic synthesis for the preparation of unsymmetrical aldehydes via hydrolysis of an oxazine. The reaction is named after the American chemist Albert Meyers.

Richard F. Heck American chemist

Richard Frederick Heck was an American chemist noted for the discovery and development of the Heck reaction, which uses palladium to catalyze organic chemical reactions that couple aryl halides with alkenes. The analgesic naproxen is an example of a compound that is prepared industrially using the Heck reaction.

Organoindium chemistry

Organoindium chemistry is the chemistry of compounds containing In-C bonds. The main application of organoindium chemistry is in the preparation of semiconducting components for microelectronic applications. The area is also of some interest in organic synthesis. Most organoindium compounds feature the In(III) oxidation state, akin to its lighter congeners Ga(III) and B(III).

Strychnine total synthesis

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Rothemund reaction

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The Saegusa–Ito oxidation is a chemical reaction used in organic chemistry. It was discovered in 1978 by Takeo Saegusa and Yoshihiko Ito as a method to introduce α-β unsaturation in carbonyl compounds. The reaction as originally reported involved formation of a silyl enol ether followed by treatment with palladium(II) acetate and benzoquinone to yield the corresponding enone. The original publication noted its utility for regeneration of unsaturation following 1,4-addition with nucleophiles such as organocuprates.

Hydrogen-bond catalysis

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Rearrangements, especially those that can participate in cascade reactions, such as the aza-Cope rearrangements, are of high practical as well as conceptual importance in organic chemistry, due to their ability to quickly build structural complexity out of simple starting materials. The aza-Cope rearrangements are examples of heteroatom versions of the Cope rearrangement, which is a [3,3]-sigmatropic rearrangement that shifts single and double bonds between two allylic components. In accordance with the Woodward-Hoffman rules, thermal aza-Cope rearrangements proceed suprafacially. Aza-Cope rearrangements are generally classified by the position of the nitrogen in the molecule :

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Krische allylation

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References

  1. Total synthesis of (+)-calyculin A. J. Am. Chem. Soc.1992, 114, 9434-9453 doi : 10.1021/ja00050a024
  2. Asymmetric Synthesis of the Squalene Synthase Inhibitor Zaragozic Acid C. J. Am. Chem. Soc.1994, 116, 12111-12112 doi : 10.1021/ja00105a085
  3. ""ACS Cope Award"". Archived from the original on 2016-03-04. Retrieved 2015-04-06.
  4. Mark Van Doren Award for Teaching. http://www.columbia.edu/cu/vpas/about/recognition.html#2
  5. An Approach to the Synthesis of CP-263,114: A Remarkably Facile Silyloxy-Cope Rearrangement. J. Am. Chem. Soc.1999, 121, 890-891. doi : 10.1021/ja983609x
  6. Total Synthesis of Leucascandrolide A. J. Am. Chem. Soc.2000, 122, 12894-12895. doi : 10.1021/ja003593m
  7. Formal Total Synthesis of Mycoticin A. J. Am. Chem. Soc.2001, 123, 341-342. doi : 10.1021/ja0035102
  8. Total Synthesis of Dolabelide D. J. Am. Chem. Soc.2006, 128, 2796-2797. doi : 10.1021/ja058692k
  9. Origins of Stereoselectivity in Strain-Release Allylations. Angew. Chem. Int. Ed.2004, 44, 938-941. doi : 10.1002/anie.200462130