Background: A tautomerism is a type of isomerization that occurs by the shifting of a double bond and the movement of a proton. Examples of tautomerisms can be seen in reactions that result in a vinyl alcohol product known as an enol. This enol product is quickly changed to the keto form. The interconversion between the keto and enol forms of a molecule can be catalyzed under both acidic and basic conditions. In most simple ketones and aldehydes, the keto form is preferred and exists in greater amounts at equilibrium. This is due to the stability of the types of bonds present in each molecule.

Question: Complete the reaction mechanism for the following keto-enol tautomerism occurring in basic conditions, clearly showing both resonance contributors. Notice that between boxes two and three the electron flow corresponding to resonance contributors should be shown. Each box requires curved arrows.

I KEEP GETTING ERROR MESSAGE:

For the enol to be obtained, the enolate ion must abstract a proton to form an alcohol. Recall that the reaction is being catalyzed in basic conditions but that the hydroxide ion was protonated in step one.