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The mechanism of the Horner-Wadsworth-Emmons reaction. The ratio of alkene isomers 5 and 6 is not dependent upon the stereochemical outcome of the initial carbanion addition and upon the ability of the intermediates to equilibrate. The electron-withdrawing group (EWG) alpha to the phosphonate is necessary for the final elimination to occur.
Triethyl phosphonoacetate is a reagent for organic synthesis used in the Horner-Wadsworth-Emmons reaction (HWE) or the Horner-Emmons modification. Triethyl phosphonoacetate can be added dropwise to sodium methoxide solution to prepare a phosphonate anion. It has an acidic proton that can easily be abstracted by a weak base.
William D. Emmons (November 18, 1924 – December 8, 2001) was an American chemist and published with William S. Wadsworth a modification to the Wittig-Horner reaction using phosphonate-stabilized carbanions, now called the Horner-Wadsworth-Emmons reaction in his honor.
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Leopold Horner (24 August 1911 – 5 October 2005) was a German chemist who published a modified Wittig reaction using phosphonate-stabilized carbanions now called the Horner–Wadsworth–Emmons reaction (HWE reaction) or Horner-Wittig reaction.
Réaction de Horner-Wadsworth-Emmons; Usage on it.wikipedia.org Reazione di Horner-Wadsworth-Emmons; Usage on it.wikibooks.org Chimica organica/Cose da fare; Usage on ja.wikipedia.org ホーナー・ワズワース・エモンズ反応; Usage on nl.wikipedia.org Horner-Wadsworth-Emmons-reactie; Usage on pt.wikipedia.org Reação de Horner ...
In the related Michaelis–Arbuzov reaction the same reactants are known to form a beta-keto phosphonate which is an important reagent in the Horner–Wadsworth–Emmons reaction on the road to alkenes. The Perkow reaction, in this respect is considered a side-reaction.
Factors governing organic reactions are essentially the same as that of any chemical reaction.Factors specific to organic reactions are those that determine the stability of reactants and products such as conjugation, hyperconjugation and aromaticity and the presence and stability of reactive intermediates such as free radicals, carbocations and carbanions.