Give a Mechanistic Explanation for the Formation of the Following

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The regioselective addition of a proton first generates a secondary carbocation,which can undergo rearrangement to a more stable 3<sup>o</sup> carbocation by two alternate pathways.One pathway results in ring expansion to a more stable 5-membered ring.This pathway is thus more likely,which would then lead to the observed product.The other pathway is less likely,since ring strain is not relieved;however,this could lead to a minor product,as shown above.

The regioselective addition of a proton first generates a secondary carbocation,which can undergo rearrangement to a more stable 3^o carbocation by two alternate pathways.One pathway results in ring expansion to a more stable 5-membered ring.This pathway is thus more likely,which would then lead to the observed product.The other pathway is less likely,since ring strain is not relieved;however,this could lead to a minor product,as shown above.

Give a Mechanistic Explanation for the Formation of the Following

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