Aldol Condensation

In some cases, the adducts obtained from the Aldol Addition can easily be converted (in situ) to α,β-unsaturated carbonyl compounds, either thermally or under acidic or basic catalysis. The formation of the conjugated system is the driving force for this spontaneous dehydration. Under a variety of protocols, the condensation product can be obtained directly without isolation of the aldol.

The aldol condensation is the second step of the Robinson Annulation.

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Mechanism of the Aldol Condensation

For the addition step see Aldol Addition

Recent Literature

An Efficient Method for the Selective Iodination of α,β-Unsaturated Ketones
Z. Wang, G. Yin, J. Qin, M. Gao, L. Cao, A. Wu, Synthesis, 2008, 3565-3568.

CBr₄ as a Halogen Bond Donor Catalyst for the Selective Activation of Benzaldehydes to Synthesize α,β-Unsaturated Ketones
I. Kazi, S. Guha, G. Sekar, Org. Lett., 2017, 19, 1244-1247.

One-Pot Synthesis of β,β-Disubstituted α,β-Unsaturated Carbonyl Compounds
M. Sugiura, Y. Ashikari, M. Nakaijima, J. Org. Chem., 2015, 80, 8830-8835.

Direct Synthesis of β,γ-Unsaturated α-Keto Esters from Aldehydes and Pyruvates
J. K. Mansaray, J. Sun, S. Huang, W. Yao, Synlett, 2019, 30, 809-812.

Organocatalytic Asymmetric Reaction Cascade to Substituted Cyclohexylamines
J. Zhou, B. List, J. Am. Chem. Soc., 2007, 129, 7498-7499.

Selective Macrocycle Formation in Cavitands
J.-M. Yang, Y. Yu, J. Rebek Jr., J. Am. Chem. Soc., 2021, 143, 2190-2193.