The alpha carbon to the carbonyl carbon: the carbon next to the carbonyl group is designated as being the in alpha position. One of the alpha hydrogens (hydrogens on the alpha carbon) will be replaced. A carbonyl compound with alpha hydrogen atom on its alpha carbon rapidly equilibrates with its corresponding enol. Tautomers are not resonance forms: tautomers are structural isomers, resonance forms are representations of contributors to a single structure, tautomers interconvert rapidly while ordinary isomers do not. Usually the keto form is the dominant one of the tautomers: keto: >99. 99, enol: <0. 01% Keto contains c=o, while enol contains c=c. Enolates: the enolates are much more nucleophilic than the enols, use base to deprotonate the alpha carbon and produce the enolate, which is resonance stabilized. Esters (cid:894)r"oor""(cid:895) and nitriles (cid:272)an also rea(cid:272)t (cid:449)ith a (cid:271)ase to produ(cid:272)e an resonan(cid:272)e sta(cid:271)ilized enolate.
