Chapter 21, Problem 40P

Interpretation Introduction

Interpretation: The structure of the two keto tautomers in equilibrium with the enediol of vitamin C are to be drawn and the reason for enediol more stable than the other tautomers is to be stated.

Concept introduction: Tautomers are isomers which differ only in the position of the hydrogen and electrons of the electronegative atom, generally oxygen. There is no change in the carbon skeleton of the compound. This phenomenon which involves simple proton transfer in an intramolecular fashion is known as tautomerism.

The very common example of tautomerism is Keto-enol tautomerism. It can be acid or base catalysed.