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

Verified step by step guidance

1. Identify the reactants: Cyclohexanone is a ketone with a six-membered ring. In an aldol condensation, it will act as both the nucleophile and electrophile due to the presence of alpha-hydrogens.
2. Determine the enolate formation: Deprotonate one of the alpha-hydrogens of cyclohexanone using a base (e.g., hydroxide ion) to form the enolate ion. The enolate ion is stabilized by resonance between the alpha-carbon and the carbonyl oxygen.
3. Perform the nucleophilic attack: The enolate ion acts as a nucleophile and attacks the carbonyl carbon of another cyclohexanone molecule, forming a beta-hydroxyketone intermediate. This step is the aldol addition.
4. Facilitate dehydration: Under heating or with a strong base, the beta-hydroxyketone undergoes elimination of water (dehydration) to form an α,β-unsaturated ketone. This involves the removal of a hydroxyl group and an alpha-hydrogen, resulting in the formation of a double bond between the alpha and beta carbons.
5. Predict the final product: The final product of the reaction is an α,β-unsaturated ketone derived from cyclohexanone. Specifically, it will be 2-cyclohexenone, which contains a conjugated double bond in the six-membered ring.

Key Concepts

Aldol Condensation

Aldol condensation is a reaction between aldehydes or ketones that contain at least one alpha-hydrogen. In this process, one molecule acts as a nucleophile and attacks the carbonyl carbon of another molecule, forming a beta-hydroxy carbonyl compound (aldol). This intermediate can then undergo dehydration to yield an alpha, beta-unsaturated carbonyl compound, which is often more stable and reactive.

Dehydration Reaction

Dehydration is the elimination of water from a compound, often occurring in organic reactions to form double bonds. In the context of aldol condensation, after the formation of the aldol product, dehydration involves the removal of a water molecule, resulting in the formation of a conjugated enone or enal. This step is crucial as it enhances the stability and reactivity of the final product.

Cyclohexanone Reactivity

Cyclohexanone is a cyclic ketone that can participate in aldol condensation due to the presence of alpha-hydrogens. Its reactivity is influenced by the ring structure, which can affect steric hindrance and the stability of intermediates. Understanding how cyclohexanone reacts in aldol condensation helps predict the products formed, including the potential for intramolecular reactions if conditions allow.