Show how you would use an aldol, Claisen, or another type of condensation to make each compound.
(a)

Verified step by step guidance

1. Step 1: Identify the target molecule and recognize the functional groups present. The compound contains an aldehyde group (-CHO) and a double bond conjugated to the aldehyde. This suggests that the molecule could be synthesized using an aldol condensation reaction.
2. Step 2: Break down the target molecule into potential precursors. In an aldol condensation, the product is typically formed by the reaction of an enolate ion with a carbonyl compound. Here, the molecule can be divided into two parts: (1) a cyclohexanone (providing the enolate) and (2) another cyclohexanone (acting as the electrophilic carbonyl compound).
3. Step 3: Write the mechanism for the aldol condensation. First, one molecule of cyclohexanone is deprotonated at the alpha-carbon by a base (e.g., NaOH) to form the enolate ion. The enolate ion then attacks the carbonyl carbon of the second cyclohexanone molecule, forming a β-hydroxyketone intermediate.
4. Step 4: Explain the dehydration step. The β-hydroxyketone intermediate undergoes elimination (E1cB mechanism) under basic or acidic conditions to lose water and form the α,β-unsaturated aldehyde product.
5. Step 5: Summarize the reaction conditions. The aldol condensation typically requires a base (e.g., NaOH or KOH) and mild heating to promote both the enolate formation and the dehydration step. Ensure the reaction is carried out under controlled conditions to avoid overreaction or polymerization.

Key Concepts

Aldol Condensation

Aldol condensation is a reaction between aldehydes or ketones that contain alpha-hydrogens, leading to the formation of β-hydroxy aldehydes or ketones. This reaction involves the nucleophilic addition of an enolate ion to a carbonyl carbon, followed by dehydration to form an α,β-unsaturated carbonyl compound. It is a key reaction in organic synthesis for building complex molecules.

Claisen Condensation

Claisen condensation is a reaction between two esters or an ester and a carbonyl compound in the presence of a strong base, resulting in the formation of a β-keto ester or a β-diketone. The reaction involves the formation of an enolate ion from one ester, which then attacks the carbonyl carbon of another ester, followed by subsequent hydrolysis. This reaction is crucial for synthesizing larger carbon skeletons in organic chemistry.

Condensation Reactions

Condensation reactions are a class of reactions where two molecules combine to form a larger molecule, typically with the loss of a small molecule such as water or methanol. In organic chemistry, these reactions are essential for forming carbon-carbon bonds and constructing complex structures. Understanding the mechanisms and conditions for these reactions is vital for effective synthesis in organic chemistry.