Lecture

Asymmetric Synthesis: Hydroboration, Epoxidation, Regioselectivity

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In course

CH-335: Asymmetric synthesis and retrosynthesis

The first part of the course presents the classical methods of asymmetric synthesis. The second part of the course introduces retrosynthesis strategies based on the disconnection approach. ...

Description

This lecture covers the asymmetric synthesis of organic compounds through hydroboration and epoxidation reactions, focusing on regioselectivity and stereoselectivity. The slides detail the mechanisms and reactivity of these reactions, including the use of mCPBA for directed epoxidation. Emphasis is placed on the stabilization of intermediates, the role of hydrogen bridge donors, and the regioselectivity hierarchy in carbocation formation.

Instructors (2)

Sandrine Gerber

Sandrine Gerber studied chemistry at the "Ecole Nationale Supérieure de Chimie de Paris" in France, where she obtained a diploma of chemical engineer in 1993. The same year she obtained a DEA (Master degree) of organic chemistry at the University Pierre et Marie Curie (Paris VI, France). From 1993 to 1996 she did a PhD in organic chemistry under the supervision of Prof. Jean-Pierre Genêt at the Ecole Nationale Supérieure de Chimie de Paris. In 1996, she moved to University of Lausanne for a post-doctoral stay under the supervision of Prof. Pierre Vogel. In 1998, she was appointed Maître-Assistante at the Institute of Organic Chemistry in the University of Lausanne. In 2003, she obtained the habilitation to direct research from the University Pierre et Marie Curie (Paris VI, France). The same year, she was appointed scientific adjunct at the EPFL and senior scientist (Maître d'Enseignement et de Recherche) in 2006. In December 2014, she was promoted to titular professor. Since September 2007, Sandrine Gerber is deputy to the director of the Institute of Chemical Sciences and Engineering (ISIC). She is also member of the Board of Directors of the Swiss Chemical Society. Since 2007, Sandrine Gerber is part-time lecturer at the university of Fribourg. She was awarded the Prize Eugene Schueller in 1997, the Prize Dufour for prospective organic chemistry in 2005 and the Werner Prize 2010. She also received a special mention in recognition of exceptional quality of pedagogic competencies in the teaching of basic sciences, given by the Direction of the School of Biology and Medicine from the University of Lausanne, in 2013. In October 2018, she will receive the Prize for Excellence in Teaching from the section of Chemistry and Chemical Engineering.

Stefano Nicolai

Teaching & PhD Courses Asymmetric synthesis and retrosynthesis CH-335 The first part of the course presents the classical methods of asymmetric synthesis. The second part of the course introduces retrosynthesis strategies based on the disconnection approach.

Official source

Related concepts (31)

Asymmetric induction

Asymmetric induction (also enantioinduction) 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. Asymmetric induction was introduced by Hermann Emil Fischer based on his work on carbohydrates. Several types of induction exist.

Organic chemistry

Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms. Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior.

Epoxide

In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. A compound containing the epoxide functional group can be called an epoxy, epoxide, oxirane, and ethoxyline.

Enantioselective synthesis

Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer.

Stereoselectivity

In chemistry, stereoselectivity is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereoisomers during a non-stereospecific creation of a new stereocenter or during a non-stereospecific transformation of a pre-existing one. The selectivity arises from differences in steric and electronic effects in the mechanistic pathways leading to the different products. Stereoselectivity can vary in degree but it can never be total since the activation energy difference between the two pathways is finite: both products are at least possible and merely differ in amount.

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Asymmetric Synthesis: Allylation and Enolate Synthesis

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Bifunctionalized Compounds: Strategies and Selectivity

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