Stobbe condensation

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The Stobbe condensation entails the reaction of an aldehyde or ketone with an ester of succinic acid to generate alkylidene succinic acid or related derivatives. [1] The reaction consumes one equivalent of metal alkoxide. Commonly, diethylsuccinate is a component of the reaction. The usual product is salt of the half-ester. The Stobbe condensation is named after its discoverer, Hans Stobbe, whose work involved the sodium ethoxide-induced condensation of acetone and diethyl succinate. [2]

Contents

An example is the reaction of benzophenone with diethyl succinate: [3]

StobbeCondensation.svg

A reaction mechanism that explains the formation of both an ester group and a carboxylic acid group is centered on a lactone intermediate (5):

Reaction mechanism StobbeMechanism.svg
Reaction mechanism

The Stobbe condensation is also illustrated by the synthesis of the drug tametraline. [4]

See also

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<span class="mw-page-title-main">Diethyl oxomalonate</span> Chemical compound

Diethyl oxomalonate is the diethyl ester of mesoxalic acid (ketomalonic acid), the simplest oxodicarboxylic acid and thus the first member (n = 0) of a homologous series HOOC–CO–(CH2)n–COOH with the higher homologues oxalacetic acid (n = 1), α-ketoglutaric acid (n = 2) and α-ketoadipic acid (n = 3) (the latter a metabolite of the amino acid lysine). Diethyl oxomalonate reacts because of its highly polarized keto group as electrophile in addition reactions and is a highly active reactant in pericyclic reactions such as the Diels-Alder reactions, cycloadditions or ene reactions. At humid air, mesoxalic acid diethyl ester reacts with water to give diethyl mesoxalate hydrate and the green-yellow oil are spontaneously converted to white crystals.

References

  1. Smith, Michael B.; March, Jerry (2006). March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. p. 1452-1455. doi:10.1002/0470084960. ISBN   9780470084960.
  2. Stobbe, H. (1899). "Condensation des Benzophenons mit Bernsteinsäureester". Justus Liebigs Annalen der Chemie. 308 (1–2): 89–114. doi:10.1002/jlac.18993080106.
  3. Johnson, W. S.; Schneider, W. P. (1950). "β-Carbethoxy-γ,γ-Diphenylvinylacetic Acid". Organic Syntheses . 30: 18. doi:10.15227/orgsyn.030.0018.
  4. Sarges R (1975). "Synthesis of Phenyl-Substituted 1-Aminotetralines". The Journal of Organic Chemistry. 40 (9): 1216–1224. doi:10.1021/jo00897a008.