Chapter 20, Problem 20.21P

Interpretation Introduction

Interpretation:

It is to be shown how to convert the given carboxylic acid into the corresponding aldehyde.

Concept introduction:

An ester, on treatment with Diisobutylaluminum hydride (DIBAH), is converted to the corresponding aldehyde at low temperature. Further reduction of an aldehyde does not take place because the reducing agent is not present in the reaction mixture. Carboxylic acid, on treatment with diazomethane $\left({\text{CH}}_{\text{2}}{\text{N}}_{\text{2}}\right)$, is converted to the corresponding methyl ester. Since a carboxylic acid is more stable than its corresponding aldehyde, it is not easily converted to the corresponding aldehyde. But acid derivatives like acid chloride and an ester can be converted to the corresponding aldehyde by using specific reducing agents. To reduce carboxylic acid to the corresponding aldehyde, it is first converted to the corresponding acid derivative like acid chloride or an ester.