Question
Question: A chemical reaction diagram is shown. The reactant is a six-membered ring with alternating single an...
A chemical reaction diagram is shown. The reactant is a six-membered ring with alternating single and double bonds, indicating a benzene ring. A hydroxyl group is attached to one of the carbon atoms of the ring. This benzene ring is connected to a carbonyl group (C=O) via a single bond. The carbonyl group is further connected to a carbon atom, which is double-bonded to another oxygen atom. This carbon atom is also bonded to a hydrogen atom. Below the reactant, there is a reaction arrow pointing to the right. Above the arrow, 'KOH' is written, indicating potassium hydroxide as a reagent. Below the arrow, a triangle is drawn, indicating heat is applied to the reaction.
It is a benzilic acid rearrangement.
Solution
Base (KOH) attacks the aldehyde carbonyl in –CO–CHO, forming an intermediate that rearranges via an aryl shift to give an α‐hydroxy carboxylate. On acid workup, the benzilic acid rearrangement product (benzilic acid derivative) is obtained.