# SN1 Reaction Involving Carboxylic Acids

Which oxygen atom is more nucleophilic in carboxylic acids?

If we look at this page, it says the carbonyl oxygen is more nucleophilic:

However, I also learned in class that $\mathrm{sp^3}$ atoms are more reactive than $\mathrm{sp^2}$ atoms.

So, in an $\mathrm{S_n1}$ reaction where the solvent is acetic acid, which oxygen attacks?

• "However, I also learned in class that $\mathrm{sp^3}$ atoms are more reactive than $\mathrm{sp^2}$ atoms.", that might apply (if so) for $C$ atoms, not for others. Anyway, I would avoid this kind of reasoning. Using the concept of hybridization is not appropriate when it comes to try to justify or predict reactivity. – Altered State Nov 20 '14 at 16:12