Question

Predict the products of aldol condensation, followed by dehydration, of the following ketones and aldehydes.(b) acetophenone

Accepted Answer

Identify the structure of acetophenone. Acetophenone is a ketone with the structure $$C_{6}H$$_{5}-CO-CH_{3}, where the carbonyl group (C=O) is directly attached to a benzene ring. Determine the enolate ion formation. Under basic conditions, the alpha-hydrogen (hydrogen attached to the carbon adjacent to the carbonyl group) of acetophenone is abstracted by a base, forming an enolate ion. The enolate ion is resonance-stabilized, with the negative charge delocalized between the alpha-carbon and the oxygen atom of the carbonyl group. Perform the aldol addition. The enolate ion acts as a nucleophile and attacks the carbonyl carbon of another molecule of acetophenone. This forms a beta-hydroxyketone intermediate, where the hydroxyl group (-OH) is attached to the beta-carbon relative to the original carbonyl group. Carry out the dehydration step. Under heating or acidic/basic conditions, the beta-hydroxyketone undergoes elimination of water (dehydration) to form an α,β-unsaturated ketone. This involves the removal of the hydroxyl group and a hydrogen atom from the alpha-carbon, resulting in the formation of a double bond between the alpha and beta carbons. Predict the final product. The final product of the aldol condensation followed by dehydration of acetophenone is an α,β-unsaturated ketone with the structure $$C_{6}H$$_{5}-CH=CH-CO-CH_{3}, where the double bond is conjugated with both the benzene ring and the carbonyl group, providing additional stability.

Predict the products of aldol condensation, followed by dehydration, of the following ketones and aldehydes.
(b) acetophenone

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Aldol Condensation

Dehydration Reaction

Acetophenone Structure