91Ó°ÊÓ

• It protonates the carbonyl oxygen of the keto tautomer.
• Water removes a proton from-carbon, forming the enol tautomer.

Therefore, the final product is cyclopentenol.

The aldol addition can occur between the same aldehyde or ketone molecules, resulting in the number of carbons from the reactant aldehyde or ketone being doubled.

• A base removes a proton from the-carbon, creating an enolate ion.
• The enolate ion is added to the carbonyl carbon at the second position of the carbonyl molecule.
• The negatively charged oxygen is protonated.

The mechanism of aldol addition is given below:

Aldol condensation is when two molecules combine by removing a small molecule like water, resulting in the formation ofunsaturated aldehyde or ketone.