Question

Major product 'P' formed in the following reaction is:

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

The Hell-Volhard-Zelinsky (HVZ) reaction specifically brominates the α-carbon of car boxylic acids and can lead to lactone formation through intramolecular cyclization.

Answer 1

The Correct Option is D

Analysis of the Hell-Volhard-Zelinsky (HVZ) Reaction:

The reaction involves the bromination of the α-carbon atom of a carboxylic acid in the presence of bromine (Br₂) and sodium bicarbonate (NaHCO₃).

Reaction Mechanism :

1. The α-carbon of the carboxylic acid is halogenated through the formation of an enol intermediate:
   CH₃-CH₂-CH(OH)-COOH \( \xrightarrow{\text{Br}_2/\text{NaHCO}_3} \) CH₃-CH₂-CBr-COOH.
2. Cyclization occurs via intramolecular nucleophilic attack of the hydroxyl group (-OH) on the α-brominated carboxylic acid, leading to the formation of a bromolactone:
   CH₃-CH₂-CBr-COOH → Cyclobromo-lactone.
3. The final product is the formation of a five-membered cyclic structure with a bromine atom at one position and a carbonyl group at another.

Analysis of Options:

1. Option (1) : Incorrect. This structure does not represent the cyclic lactone product.
2. Option (2) : Incorrect. This structure has a hydroxyl (-OH) group instead of a bromine atom.
3. ption (3): Incorrect. This structure has multiple bromine atoms, which are not consistent with the reaction mechanism.
4. Option (4) : Correct. This is the bromolactone formed as the major product.O

Conclusion: The major product is represented by option (4).