Question

Consider the following compounds:

Which of the following show hyperconjugation?

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• A. I and III
• B. I only
• C. II only
• D. III only

Answer 1

The correct option is D III only

Hyperconjugation shown when there is presence of $\alpha -H$ in the compound.
I and II do not have $\alpha -H$ and will not show tautomerism.



Bridge carbon atom does not take participate in tautomerism. (III) has one $\alpha -H$ and will show tautomerism.
Only I shows hyperconjugation.