Keto–enol tautomerism

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Presentation transcript:

Keto–enol tautomerism Keto–enol tautomerism (A) Illustration of a ketone and its enol form, and the mechanism of this reaction in the presence of acid and base. For the majority of species, the equilibrium lies towards the ketone rather than the enol. (B) The tautomerization of glucose gives an ene–diol, because there is an alcohol group adjacent to the carbonyl (diol, two alcohols). If, in the reverse reaction the carbonyl group is formed at the alcohol adjacent to the original carbonyl in the starting material, then an isomer of glucose, fructose, is formed. Amanda L. Jonsson et al. Essays Biochem. 2017;61:401-427 ©2017 by Portland Press Ltd