asymmetric synthesis

asymmetric synthesis
Chemical reaction by which unequal amounts of two product isomers are formed.

It is normally not possible to synthesize from materials that do not have optical activity (i.e., are not chiral) one stereoisomer of a chiral compound without the other, but use of a chiral auxiliary, such as an enzyme or other catalyst, a solvent, or an intermediate, can force the reaction to produce predominantly or only one isomer. Asymmetric syntheses are often called stereoselective; if one product forms exclusively, it is stereospecific.

* * *

      any chemical reaction that affects the structural symmetry in the molecules of a compound, converting the compound into unequal proportions of compounds that differ in the dissymmetry of their structures at the affected centre. Such reactions usually involve organic compounds (organic compound) in which the symmetrical structural feature is a carbon atom bonded to four other atoms or groups of atoms, of which two are alike; in the asymmetric synthesis, one of the identical groups is preferentially modified or replaced, so that the product is a mixture of two dissymmetric compounds, one of which predominates.

      Asymmetric reactions result from the influence of some dissymmetry in the reacting system, such as the presence of a dissymmetric centre in the molecule, a dissymmetric solvent or catalyst, or circularly polarized light, in which the plane of vibration of the electromagnetic fields rotates in either a right-handed or a left-handed sense.

      Asymmetric syntheses often are called stereoselective; if one of the products forms exclusively, the reaction is called stereospecific.

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Asymmetric synthesis — Asymmetric synthesis, also called chiral synthesis, enantioselective synthesis or stereoselective synthesis, is organic synthesis which introduces one or more new and desired elements of chirality. [GoldBookRef|title=asymmetric synthesis| file =… …   Wikipedia

  • asymmetric synthesis — asimetrinė sintezė statusas T sritis chemija apibrėžtis Sintezė, kurios metu susidaro nevienodas kiekis stereoizomerų, turinčių naują chiralinį centrą. atitikmenys: angl. asymmetric synthesis rus. асимметрический синтез …   Chemijos terminų aiškinamasis žodynas

  • asymmetric synthesis — noun chemistry : a process that directly produces an optically active compound (as one containing an asymmetric carbon atom) from symmetrically constituted molecules without requiring resolution of a racemic mixture …   Useful english dictionary

  • asymmetric synthesis — noun The synthesis of a specific enantiomer of a compound (or of a mixture containing more of one enantioner than the other) …   Wiktionary

  • Asymmetric induction — (also enantioinduction) in stereochemistry 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,… …   Wikipedia

  • Asymmetric dimethylarginine — IUPAC name (2S) 2 Amino 5 [(amino dimethylaminomethylene)amino]pentanoic acid …   Wikipedia

  • Asymmetric catalytic reduction — is the use of various chiral catalysts to reduce a prochiral organic compound to obtain a chiral product. This is one of the several techniques used in chiral synthesis.Typically, a transition metal is used with a bulky chiral ligand to such that …   Wikipedia

  • Enantioselective synthesis — Enantioselective synthesis: Sharpless epoxidation Enantioselective synthesis, also called chiral synthesis, asymmetric synthesis or stereoselective synthesis, is organic synthesis that introduces one or more new and desired elements of… …   Wikipedia

  • Organic synthesis — This article is about artificial synthesis of organic compounds. For the journal Organic Syntheses, see Organic Syntheses. For synthesis in organisms, see Biosynthesis. Organic synthesis is a special branch of chemical synthesis and is concerned… …   Wikipedia

  • Oseltamivir total synthesis — concerns the total synthesis of the antiinfluenza drug oseltamivir marketed by Hoffmann La Roche under the trade name Tamiflu. Its commercial production starts from the biomolecule shikimic acid harvested from Chinese star anise with a limited… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”