A tautomerization reaction interconverts two constitutional isomers of an organic molecule, referred to as tautomers, which differ only by the positions of hydrogen atoms. The scheme below shows how the reaction typically takes place at the ketone functional group of an organic molecule. The ketone form of the molecule is commonly referred to as the “keto” form of the molecule, while the alcohol form is commonly referred to as the “enol” form of the molecule.