Question

The structural feature in carbonyl compound for Aldol condensation is:

• A. Presence of at least one β-hydrogen
• B. Presence of at least one α-hydrogen
• C. Concentrated base
• D. Lack of α-hydrogen

Hint:

Aldol condensation requires the presence of α-hydrogen to form the enolate ion for the reaction to proceed.

Answer 1

The Correct Option is B

Step 1: Aldol Condensation Explained.
Aldol condensation is a reaction that produces a β-hydroxy ketone or aldehyde. It occurs when two aldehyde or ketone molecules react in the presence of a base. The mechanism involves the formation of an enolate ion via the removal of an α-hydrogen.
Step 2: Significance of α-Hydrogen.
The essential requirement for Aldol condensation is an α-hydrogen. This hydrogen atom is abstracted by the base, generating an enolate ion. This enolate ion then performs a nucleophilic attack on the carbonyl carbon of a second molecule.
Step 3: Evaluating Alternative Options.
- Option 1: β-hydrogen is incorrect. The α-hydrogen is the crucial component for the reaction to proceed.- Option 3: Concentrated base is necessary for the reaction, but the presence of α-hydrogen is the defining characteristic.- Option 4: Lack of α-hydrogen would inhibit enolate formation, thereby halting the reaction. Final Answer: \[\boxed{\text{The correct answer is the presence of at least one α-hydrogen.}}\]