Hannah

Tautomers of Acetylacetone (C₅H₈O₂)

Keto = ketone

Enol = alcohol

may also be referred to as an alkenol

Usually the keto tautomer is favored

The basic reaction

Why Tautomerization Matters

-Different solvents may change the equilibrium of the keto- and enol- forms

-Tautomers in DNA replication have been hypothesized to contribute to mutagenic mispairings

-"whereas in RNA, minor tautomeric forms have been proposed to enhance the structural and functional diversity of RNA enzymes and aptamers" (https://rnajournal.cshlp.org/content/21/1/1.full.html)

Keto Acetylacetone

Proton NMR (Hartree-Fock)

Proton NMR shifts:File:NMR-Chemical-Shift-PPM-Range-and-Values-Table-.png

Enol Acetylacetone

Proton NMR (Hartree-Fock)

Proton NMR shifts:File:NMR-Chemical-Shift-PPM-Range-and-Values-Table-.png

N.B. Hydrogen bonding deshields the proton, further increasing the chemical shift