[ostudent]

Hello all,

I have an exam this wednesday so I would really appreciate your feedback on this.
According to my textbook, the alpha,beta-unsaturated carbonyl compound and this glycol becomes a ring.

I've shown my work. The mechanism in pink is all guesswork.

My main questions:
1. Why does ROH attack the carbonyl C rather than undergo conjugate addition? Is this always the case in acidic conditions with all nucleophiles, even modest ones like ROH?
2. Is this mechanism feasible?

Thank you so much for your time and thoughts.

[spirochete]

It's called acetal formation. It is more likely to be favorable under conditions where water is being removed, and it also more favorable when a diol is used as the reactant, so that a cyclic acetal is formed.

And your mechanism makes sense. It would be best to also include a resonance structure for any carbocation that shows how the adjacent oxygen is making a double bond.