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Question
Convert the following:
Acetaldehyde to But-2-enal
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Solution
Aldol condensation (in presence of dil. \[\ce{NaOH}\]) followed by dehydration.
\[\begin{array}{cc}
\phantom{}\ce{\underset{Acetaldehyde}{CH3CHO} ->[dil. NaOH] CH3 - CH - CH2 - CHO ->[Δ][-H2O] \underset{\underset{(Adol condensation product)}{But-2-enal}}{CH3 - CH} = CH - CHO}\\
|\phantom{.........................}\\
\ce{\underset{\underset{(Adol)}{3-Hydroxybutanal}}{OH}}\phantom{.......................}\\
\end{array}\]
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\phantom{}\ce{O}\\
\phantom{}||\\
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\end{array}\]
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