Keto-Enol Tautomers Tautomers are isomers which differ in the placement of a hydrogen. One may be converted to the other. 。In base: Step 1:Deprotonation on C Step 2:Reprotonation on O HO: C=( enol form keto form enolate ion (vinyl alcohol) Chapter 22 5Chapter 22 5 Keto-Enol Tautomers • Tautomers are isomers which differ in the placement of a hydrogen. • One may be converted to the other. • In base: =>