3Reactions in which a larger molecule is formed from smaller components, with the elimination of a very small by-product such as water are termed Condensations.
Hence the following examples are properly referred to as aldol condensations. The dehydration step of an aldol condensation is also reversible in the presence of acid and base catalysts.
Consequently, on heating with aqueous solutions of strong acids or bases, many α, β-unsaturated carbonyl compounds fragment into smaller aldehyde or ketones, a process known as the retro-aldol reaction.
reverse reactions are retro aldol reactions
