Q18P - Organic Chemistry (Mcmurry)

Question

When o-phthalaldehyde is treated with base, o-(hydroxymethyl)benzoic acid is formed. Show the mechanism of this reaction.

Step-by-Step Solution

Answer

                                          Formation of desired product

Step 1: Cannizaro reaction

Cannizzaro reaction is a base-induced disproportionation reaction. In this reaction, two moles of aldehyde react to give one molecule of carboxylic acid and another molecule of primary alcohol.

Step 2: Mechanism of this reaction

Initially, the addition of hydroxyl group to O-phthaladehyde takes place, then expulsion and addition of hydride ion occur. This shift of proton takes place followed by protonation to get the desired compound.

                                                       Formation of the desired product