# Hydrolysis of epoxide

There are two possibilities:

• Oxonium ion formation
• Cleaving of epoxide

Firstly, I don't know if epoxide is more reactive than carbonyl group. If epoxide reacts with the proton,

In the above mechanism, an unstable carbocation is formed because its near a carbonyl group which is electron withdrawing:

• The carbocation formation don't occurs. It's a concerted step. – Koba Dec 20 '15 at 15:28
• Why? How do you know it has to be concerted? – Aditya Dev Dec 20 '15 at 15:29
• You are correct in your last structure. This carbocation is very unstable, because this the mechanism is concerted. See the two products, whats more stable? – Koba Dec 20 '15 at 15:40
• Both are equally stable? Are you referring steric repulsion? But the product in my answer is stabilized by conjugation which is not there in the answer given. – Aditya Dev Dec 20 '15 at 15:43
• In your answer the second carbocation seems unstable and the final product in your answer is more unstable in relationship the correct answer. I think that the product that you propound are a subproduct. – Koba Dec 20 '15 at 15:58

I would go with your approach but your final product is unstable due to high repulsion's by $\pi$ electrons.