Question

A mixture of cinnamaldehyde and crotonaldehyde is treated with concentrated alkali, Which statement is incorrect about the above reaction?
$C_6H_5 - \overset{\beta}{C}H = \overset{\alpha}{C}H - CHO + \overset{\gamma}{C}H_3 - \overset{\beta}{C}H = \overset{\alpha}{C}H - CHO \xrightarrow{OH^-}$

• A. Aldol condensation takes place and $\alpha$-carbon atom of crotonaldehyde provides the carbanion
• B. Aldol condensation takes place and $\alpha$-carbon atom of cinnamaldehyde provides the carbanion
• C. Aldol condensation takes place and $\gamma$-carbon atom of crotonaldehyde provides the carbanion
• D. Cannizaro reaction takes place of crotonaldehyde is reduced whereas cinnamaldehyde is oxidised

Answer 1

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

Removal of $\gamma$-hydrogen of crotonaldehyde provides more stable allylic carbanion, hence $\gamma$ carbon (not $\alpha$ ) provides the carbanion (nucleophile) for carbonyl carbon of cinnamaldehyde