Chemistry - Hydrocarbon Question with Solution | TestHub

Question Explanation:  

Question is asking about the reason that why, compound A does not undergo decarboxylation reaction.

Concept : This question is based on Bredt's Rule.

Solution:

CO₂ is not released in this case, ketone is present at bridge head position & bridge head carbon can never be sp² hybridized (Intermediate does not follow Bredt's rule).

Bredt’s rule states that a double bond (C=C) cannot be formed at the bridgehead carbon of a small bicyclic system (usually with bridges <8 atoms) because the required planarity for π-bond formation cannot be achieved — the carbon’s orbitals cannot align properly due to ring strain.

In decarboxylation, a CO₂ group is removed, forming a double bond at the same carbon.

If that carbon is a bridgehead carbon, forming a C=C there would violate Bredt’s rule since the π- bond cannot be planar at that position.