When a primary carbocation is formed adjacent to a highly strained cyclobutane ring (e.g., cyclobuty — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

A primary carbocation adjacent to a strained 4-membered ring is highly unstable. It relieves significant angle and torsional strain by undergoing an alkyl shift where one of the ring carbon-carbon bonds breaks and reattaches to the carbocation center. This expands the ring to a 5-membered ring containing a more stable secondary carbocation.