Keto Enol Tautomerism

Keto Enol Tautomerism

The word tautomerism comes from the Greek word tauto which means same and meros means parts. The phenomenon in which two isomeric forms having different functional groups are spontaneously interconvertible and can exist in dynamic equilibrium. The two forms in tautomeric equilibrium are called tautomers of each other. Aldehydes, ketones and esters may exhibit tautomerism.
The two tautomeric forms (i.e. keto and enol) which are in equilibrium is called keto enol tautomerism. Example- Two tautomeric forms of ethylacetoacetate are given below-

Other examples of keto enol tautomerism-


Hints: Molecule A and B violates Bredt's rule
Molecule C does not violates Bredt's rule

What statement is correct for keto-enol tautomerism?

A. Tautomerism can be catalyzed by acid and base both.
B. Tautomers are present in a dynamic equilibrium state.
C. Generally keto form is more stable than enol form in simple ketone.
D. All of the above.

Active Methylene Compounds

 Share