A theoretical study on the oxidation mechanism of triose reductone in reference to L-ascorbic acid

Abstract

The oxidation of triose reductone H—CO—C(OH)=C(OH)—H (which has the same functional group as L-ascorbic acid) to dehydroreductone is investigated by abinitio molecular orbital computations. The geometries of the substrate, oxidized product, and of six possible intermediate species are optimized by gradient methods at the STO-3G basis set level. All the species are found to be planar and stable molecules by the vibrational analysis. The most possible oxidation route is shown to consist of four steps. The combination of the enediol and carbonyl groups in the deprotonated molecule 2 gives an effective π conjugation for the electron removal. The oxidation process of L-ascorbic acid is discussed on the basis of the results for triose reductone.