Compounds containing an enediol structure stabilized by
conjugation and
hydrogen bonding with an adjacent carbonyl group,
RC(OH)=C(OH)C(=O)R.
They are strong reducing agents, fairly strong acids and commonly derived from
saccharides by
oxidation at the carbon atom alpha to the carbonyl function, e.g. ascorbic acid.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1363