Keto-enol tautomerism

Keto-enol tautomerism keto form

R

O

OH

C

C

CH3

R

CH2

enol form

“Tautomers” Tautomers” are isomers that cannot be separated because they interconvert too rapidly. „ “Keto” Keto” form favored over “enol “enol”” form. „

Keto-enol tautomerism „ KetoKeto-enol tautomers interconvert under

any condensedcondensed-phase conditions. „ Mechanism under basic conditions:

R

O

O

C

C

CH2

Base R

H

Base

CH2

OH R

C

CH2

H

Keto-enol tautomerism „ KetoKeto-enol tautomers interconvert under

any condensedcondensed-phase conditions. „ Mechanism under acidic conditions: H Acid

O R

C

CH2 H

OH R

C

OH CH2

Acid R

C

CH2

H

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