Enolisierbare

Enolisierbare, often rendered in English as enolizable, is a term used in organic chemistry to describe carbonyl-containing compounds that can undergo enolization to give the corresponding enol tautomer. The property depends on the presence of at least one hydrogen on the alpha carbon, the carbon adjacent to the carbonyl group. If such a hydrogen is absent, the compound is typically considered non-enolizable under ordinary conditions.

Enolization involves keto–enol tautomerism and can be induced by acid or base catalysis. In many cases, the keto form is favored, but equilibrium with the enol form is established and can be shifted by solvent, temperature, and substituents. Substrates commonly enolizable include aldehydes and ketones with α-hydrogens, many esters and amides, and some nitriles and related carbonyl derivatives. Compounds lacking alpha-hydrogens, such as benzaldehyde and formaldehyde, are generally non-enolizable.

The enol or enolate form is a key reactive intermediate in organic synthesis. Enolates are typically generated by deprotonation at the alpha position with strong bases (for example, LDA, NaH, or KH) or by equilibration of enols. Enolates and their equivalents, including silyl enol ethers, serve as nucleophiles in aldol and related condensations, Michael additions, and various alkylations and acylations.

Limitations include reduced enolization rates for certain substrates due to resonance stabilization of the carbonyl, steric hindrance, or lack of suitable α-hydrogens. Non-enolizable substrates may still participate in alternative reaction pathways, but do not form enolates under standard conditions.