Question

Which of the following compound(s) can undergo aldol condensation?

• A. Phenyl acetaldehyde
• B. 2-Methylpentanal
• C. Benzaldehyde
• D. 1-Phenylpropanone

Answer 1

Answer: (A), (B), (D)

1-Phenylpropanone

An aldol condensation is a condensation reaction in which an enol or an enolate ion reacts with a carbonyl compound to form a $\beta$-hydroxyaldehyde or $\beta$-hydroxyketone, followed by dehydration to an $\alpha ,\beta$-unsaturated aldehyde.
Aldol condensation occurs in aldehydes having $\alpha$-hydrogen.
Phenyl acetaldehyde,2-Methylpentanal,1-Phenylpropanone have $\alpha$-hydrogen. Thus they can undergo aldol condensation.
Benzaldehyde does not have $\alpha$-hydrogen thus it will undergo aldol condensation. Hence correct options are (a),(b) and (d).