Dieckmann condensation

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The Dieckmann condensation is the intramolecular chemical reaction of diesters with base to give β-ketoesters.[1][2][3][4][5] It is named after the German chemist Walter Dieckmann (1869–1925). The equivalent intermolecular reaction is the Claisen condensation.

The Dieckmann condensation

Reaction Mechanism[edit]

The acidic hydrogen between the two carbonyl groups is deprotonated in step four . Protonation with a Brønsted-Lowry acid (H3O+ for example) re-forms the β-keto ester. [6] This deprotonation step is the driving force for this reaction.

Dieckmann Condensation reaction mechanism for the example given.

Owing to the steric stability of five- and six-membered ring structures, these will preferentially be formed. 1,4- and 1,6 diesters will form five-membered cyclic β-keto esters, while 1,5- and 1,7 diesters will form six-membered β-keto esters.[7]

See also[edit]

References[edit]

  1. ^ Dieckmann, W. Ber. 1894, 27, 102 & 965
  2. ^ Dieckmann, W. Ber. 1900, 33, 595 & 2670
  3. ^ Dieckmann, W. Ann. 1901, 317, 51 & 93
  4. ^ Schaefer, J. P.; Bloomfield, J. J. (1967). "The Dieckmann Condensation (Including the Thorpe-Ziegler Condensation)". Organic Reactions 15: 1–203. doi:10.1002/0471264180.or015.01. 
  5. ^ Davis, B. R.; Garrett, P. J. Comp. Org. Syn. 1991, 2, 806-829. (Review)
  6. ^ Janice Gorzynski Smith (2007). Organic Chemistry (2nd ed.). pp. 932–933. ISBN 978-0073327495. 
  7. ^ "Dieckmann Condensation". Organic Chemistry Portal.