Q6(d). HCl with 1-methyl-1-vinylcyclobutane: ring expansion
Write the mechanism for the following conversion. [1-methyl-1-vinylcyclobutane treated with HCl; scheme given in the paper]
Answer in brief
Protonation gives a secondary carbocation; a ring C–C bond shifts (ring expansion) to give a tertiary cyclopentyl cation, which takes up Cl⁻.
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Coversring expansioncarbocation rearrangement1,2-alkyl shiftHCl additionMarkovnikov
All parts of Question 6
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