# Mechanism for the conversion of an unsaturated alkyl halide to an alcohol

Question:

Predict the mechanism for the following reaction:

Attempt:

I thought it will proceed through SN1 mechanism as $\ce{H_2O}$ is involved (solvolysis). So I proceeded with the formation of a primary carbocation, which then rearranges via 1,2 methyl shift. Then the nucleophilic attack of $\ce{OH^{-}}$ leads to the following product, which is different form the required one.

Can any further steps lead to the required product or am I wrong from the start (most probably)?

For what it's worth, this reaction does not appear in the literature. So, whether it actually forms the product or not is anybody's guess.

However, if I had to suggest a mechanism... I would note first that an SN1 reaction on a primary centre, as you have proposed, is difficult. I think it more likely that the alkene assists in the expulsion of the chloride.

The resulting cyclopropylmethyl carbocation is stabilised and is electrophilic at multiple sites. I have only drawn one resonance form, but there are a few more. Attack of water at the tertiary carbon leads to the desired product after deprotonation.