Under basic aldol condensation of acetaldehyde, the aldol product can dehydrate to which compound?

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Multiple Choice

Under basic aldol condensation of acetaldehyde, the aldol product can dehydrate to which compound?

In this reaction, two acetaldehyde molecules undergo the typical aldol condensation: under base, one molecule forms an enolate that attacks the carbonyl of another, giving a beta-hydroxy aldehyde. That product is 3-hydroxybutanal. Under basic conditions, dehydration then removes the hydroxyl from the beta position and a proton from the alpha position, forming a C=C bond between the alpha and beta carbons. The result is an alpha,beta-unsaturated aldehyde, specifically crotonaldehyde (trans-2-butenal). This conjugated enal is the favored dehydration product, whereas the non-dehydrated aldol adduct (or simple starting materials) would correspond to the other options.

In this reaction, two acetaldehyde molecules undergo the typical aldol condensation: under base, one molecule forms an enolate that attacks the carbonyl of another, giving a beta-hydroxy aldehyde. That product is 3-hydroxybutanal. Under basic conditions, dehydration then removes the hydroxyl from the beta position and a proton from the alpha position, forming a C=C bond between the alpha and beta carbons. The result is an alpha,beta-unsaturated aldehyde, specifically crotonaldehyde (trans-2-butenal). This conjugated enal is the favored dehydration product, whereas the non-dehydrated aldol adduct (or simple starting materials) would correspond to the other options.

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