How can I predict the product of the reaction of 2-methyltetrahydrofuran with HI? I am supposed to explain why treatment of 2-methyltetrahydrofuran with hydrogen iodide leads to the formation of 5-iodopentan-2-ol. However, I am getting stuck as it seems that the less stable primary carbocation is being preferentially formed, leading to the product. Is my mechanism incorrect?
Initially, the oxygen in the ring gets protonated. However, there is no formation of a carbocation. The ring opening proceeds by an SN2 pathway, where iodide ion attacks at the less hindered carbon: