Question

Major product of the following reaction is

 

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The Correct Option is D

To determine the major product of this reaction, we need to understand the reaction mechanism involved.

The given reaction involves an acylation reaction with 2 equivalents of HBr on an allyl vinyl ether. The first step is the protonation of the ether oxygen by HBr, which leads to the cleavage of the C-O bond.

1. Protonation: The oxygen atom in the ester group is protonated by HBr, giving rise to a good leaving group.
2. Cleavage: The C-O bond is cleaved, forming a carbocation intermediate at the more stable position, which is typically the more substituted carbon atom.
3. Nucleophilic Attack: A bromide ion attacks the carbocation, resulting in the addition of a bromine atom to the molecule.
4. Addition of Second HBr: The process is repeated for the newly formed double bond, leading to the addition of another bromine atom.

The result is the addition of bromine atoms to the structure at both reactive sites, following Markovnikov's rule, where the addition occurs at the more substituted carbon.

The major product thus formed is as shown in the above image, where both double bonds have been substituted with bromine atoms as per the regioselectivity rules for electrophilic addition reactions. This matches the correct answer provided.