Allylic strain

Allylic strain

Allylic strain or 1,3-allylic strain in organic chemistry and its associated strain energy results from an unfavorable molecular conformation for the allyl group. The simplest representative of the allyls, propene, in its ground state has the methyl C-H bond eclipsed with the carbon carbon double bond. When this bond is pointing away the resulting unfavorable conformation is called bisected.

The activation energy for rotating around the allyl CC bond is 1.98 kcal/mol ["Conformational analysis. LXIV. Calculation of the structures and energies of unsaturated hydrocarbons by the Westheimer method"Norman L. Allinger, Jerry A. Hirsch, Mary Ann Miller, and Irene J. Tyminski J. Am. Chem. Soc.; 1968; 90(21) pp 5773 - 5780; DOI|10.1021/ja01023a021] .

This type of strain also extends to carbonyls.

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Strain energy — In a molecule, strain energy is released when the constituent atoms are allowed to rearrange themselves in a chemical reaction or a change of chemical conformation in a way that:* angle strain, * torsional strain, * ring strain and/or steric… …   Wikipedia

  • Nazarov cyclization reaction — The Nazarov cyclization reaction (often referred to as simply the Nazarov cyclization) is a chemical reaction used in organic chemistry for the synthesis of cyclopentenones. The reaction is typically divided into classical and modern variants,… …   Wikipedia

  • Pentane interference — or syn pentane interaction is the steric hindrance that the two terminal methyl groups experience in one of the chemical conformations of n pentane. The possible conformations are combinations of anti conformations and gauche conformations and… …   Wikipedia

  • Allylspannung — Allyl System Die Allylspannung (eigentlich 1,3 Allylspannung oder englisch 1,3 Allylstrain) ist ein Begriff aus der organischen Chemie und wurde 1968 von Francis Johnson definiert.[1] Man versteht darunter die Wechselwirkung zwischen den 1 und 3… …   Deutsch Wikipedia

  • Ene reaction — The Ene reaction (also known as the Alder ene reaction) is a chemical reaction between an alkene with an allylic hydrogen (the ene) and a compound containing a multiple bond (the enophile), in order to form a new σ bond with migration of the ene… …   Wikipedia

  • Aziridine — Chembox new ImageFileL1 = Aziridine.png ImageSizeL1 = 100px ImageFileR1 = Aziridine3d.png ImageSzieR1 = 100px IUPACName = Aziridine OtherNames = Azacyclopropane, Ethylene imine Section1 = Chembox Identifiers CASNo = 151 56 4 PubChem = SMILES =… …   Wikipedia

  • Polymer degradation — is a change in the properties tensile strength, colour, shape, etc of a polymer or polymer based product under the influence of one or more environmental factors such as heat, light or chemicals. These changes are usually undesirable, such as… …   Wikipedia

  • List of organic reactions — Well known reactions and reagents in organic chemistry include Contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z    See also   Ext …   Wikipedia

  • Aldol reaction — The aldol reaction is a powerful means of forming carbon–carbon bonds in organic chemistry.[1][2][3] Discovered independently by …   Wikipedia

  • Polythiophene — The monomer repeat unit of unsubstituted polythiophene …   Wikipedia

Share the article and excerpts

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