Dieckmann Condensation
The Dieckmann Condensation is an intramolecular variant of the Claisen Condensation. The reaction is most commonly used to prepare 5 or 6 membered ring ß-keto esters. The formation of 5 membered rings tends to be faster than 6 membered rings, although the 6 membered ring products are generally more thermodynamically stable. Ring formation becomes progressively more difficult to accomplish as the ring size of the desired product increases.
The reaction typically employs the sodium alkoxide of the alcohol that corresponds to the alcoholic moiety of the ester functional groups. The reaction can also be promoted by the use of one equivalent of sodium hydride and a catalytic amount of the corresponding alcohol.
The Dieckmann Condensation generally cannot be used to prepare small, highly strained ring systems. Rather than form a three membered ring, diethyl succinate undergoes an intermolecular Claisen Condensation followed by a Dieckmann Condensation to afford the six membered ring compound instead of reacting to form the three membered ring ß-keto ester as shown below.
See 3-quinuclidone hydrochloride for an example of a laboratory procedure for the Dieckmann condensation.
References:
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Dieckmann, W. Ber., 1900, 33, 595, 2670.
Dieckmann, W. Ann., 1901, 317, 51, 93.
Schaefer, J.P.; Bloomfield, J.J. Org. React., 1967, 15, 1-203.
J. Org. Chem., 1998, 63, 4069-4078.
T. R. Hoye, V. Dvornikovs, E. Sizova, Org. Lett., 2006, 8, 5089-5091.
Davis, B. R.; Garrett, P. J. Comp. Org. Syn. 1991, 2, 806-829. (Review)
Janice Gorzynski Smith. Organic Chemistry: Second Ed. 2008. pp 932-933.
