Predict the mechanism for the following reaction:

conversion of an unsaturated alkyl halide to an alcohol


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)?

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1 Answer 1


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.

Loss of 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.

Formation of desired product


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