Dieckmann condensation

Dieckmann condensation
Named after	Walter Dieckmann
Reaction type	Ring forming reaction
Identifiers
Organic Chemistry Portal	dieckmann-condensation
RSC ontology ID	RXNO:0000065

The Dieckmann condensation is the intramolecular chemical reaction of diesters with base to give β-keto esters.^[1] It is named after the German chemist Walter Dieckmann (1869–1925).^[2]^[3] The equivalent intermolecular reaction is the Claisen condensation. Dieckmann condensations are highly effective routes to 5-, 6-, and 7-member rings, but poor for larger rings.^[4]

Reaction mechanism

Deprotonation of an ester at the α-position generates an enolate ion which then undergoes a 5-exo-trig nucleophilic attack to give a cyclic enol. Protonation with a Brønsted-Lowry acid (H₃O⁺ for example) re-forms the β-keto ester.^[5]

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


Animation of the reaction mechanism

References

^ Davis, B. R.; Garrett, P. J. Compr. Org. Synth. 1991, 2, 806-829. (Review)
^ Kwart, Harold; King, Kenneth (1969). "Rearrangement and cyclization reactions of carboxylic acids and esters". In S. Patai (ed.). PATAI'S Chemistry of Functional Groups: Carboxylic Acids and Esters (1969). pp. 341–373. doi:10.1002/9780470771099.ch8. ISBN 9780470771099.
^ 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. ISBN 0471264180.
^ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, p. 1453, ISBN 978-0-471-72091-1
^ Janice Gorzynski Smith (2007). Organic Chemistry (2nd ed.). pp. 932–933. ISBN 978-0073327495.
^ "Dieckmann Condensation". Organic Chemistry Portal.

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[1] Davis, B. R.; Garrett, P. J. Compr. Org. Synth. 1991, 2, 806-829. (Review)

[2] Kwart, Harold; King, Kenneth (1969). "Rearrangement and cyclization reactions of carboxylic acids and esters". In S. Patai (ed.). PATAI'S Chemistry of Functional Groups: Carboxylic Acids and Esters (1969). pp. 341–373. doi:10.1002/9780470771099.ch8. ISBN 9780470771099.

[3] 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. ISBN 0471264180.

[4] Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, p. 1453, ISBN 978-0-471-72091-1

[5] Janice Gorzynski Smith (2007). Organic Chemistry (2nd ed.). pp. 932–933. ISBN 978-0073327495.

[6] "Dieckmann Condensation". Organic Chemistry Portal.

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Reaction mechanism

Further reading

See also

References