Chapter 11, Problem 11.34P

Interpretation Introduction

Interpretation: A stepwise mechanism for the following tautomerization is to be drawn.

Concept introduction: Keto-enol tautomerism refers to the existence of chemical equilibrium between a keto form of a ketone or an aldehyde and an enol for of an alcohol. Notably, the enol and keto forms are called as ‘tautomers’ of each other. Conversion of one form to another deals with the movement of an alpha hydrogen and the reorganization of bonding electrons. Carbonyl compounds (compounds having C=O bond) is generally in rapid equilibrium with its enol tautomer, which contains a pair of doubly bonded atoms of carbon in the vicinity to a hydroxyl group. At equilibrium, for most ketones the keto form is predominant. The deprotonated intermediate in the keto-enol interconversion is called as ‘enolate anion’.