Aldol Reaction

The aldol reaction is an addition reaction of a ketone or an aldehyde with a hydrogen atom at the α-position and another ketone or aldehyde to give a β-hydroxy carbonyl compound. In this reaction, an enol or an enolate, generated by the treatment of the carbonyl compound with an acid or a base, nucleophilically adds to the other carbonyl compound to give the corresponding target. Furthermore, the β-hydroxy group can be easily removed to afford an α,β-unsaturated carbonyl compound. The aldol reaction has had some problems so far, e. g., control of the regioselectivity of the double bond of the enolates during preparation when preparing, control of the stereoselectivity of the product, suppression of multiple condensation and dihydroxylation. However, stereoselective aldol reactions such as the Mukaiyama aldol reaction and asymmetric reactions such as the Evans aldol reaction have been reported. Since then, the breadth of applications of this reaction has been widespread and the aldol reaction has contributed the stereoselectivew synthesis of chain hydrocarbon compounds.