Vicinal diols reaction with periodic acid

A reaction characteristic of vicinal diols is their oxidative cleavage on treatment with periodic acid (HIO4) The carbon-carbon bond of the vicinal diol unit is broken and two carbonyl groups result Periodic acid is reduced to iodic acid (HIO3)... 

The mechanism of the cleavage of vicinal diols can be represented by the reaction of diols with periodic acid, HIO4 or H5IO6 (equation 296). 

Oxidative cleavage of vicinal diol functions in carbohydrates occurs with periodic acid (HIO4) or sodium metaperiodate (NaI04). The reaction proceeds through a cyclic intermediate and is similar to what we encountered with diols in Section 15.11. 

Periodic acid oxidation (Section 15 12) finds extensive use as an analytical method m carbohydrate chemistry Structural information is obtained by measuring the number of equivalents of periodic acid that react with a given compound and by identifying the reaction products A vicinal diol consumes one equivalent of penodate and is cleaved to two carbonyl compounds... 

The oxidative cleavage of the central carbon-carbon bond in a vicinal diol 1, by reaction with lead tetraacetate or periodic acid, yields two carbonyl compounds 2 and 3 as products. 

Mechanisms involving glycol bond fission have been proposed for the oxidation of vicinal diols, and hydride transfer for other diols in the oxidation of diols by bromine in acid solution.The kinetics of oxidation of some five-ring heterocyclic aldehydes by acidic bromate have been studied. The reaction of phenothiazin-5-ium 3-amino-7-dimethylamino-2-methyl chloride (toluidine blue) with acidic bromate has been studied. Kinetic studies revealed an initial induction period before the rapid consumption of substrate and this is accounted for by a mechanism in which bromide ion is converted into the active bromate and hyperbromous acid during induction and the substrate is converted into the demethylated sulfoxide. 

Sodium periodate (sodium metaperiodate), NaI04 (mp 300 °C dec), which is commercially available, is applied mainly in aqueous or aqueous-alcoholic solutions. Like the free periodic acid, sodium periodate cleaves vicinal diols to carbonyl compounds [762], This reaction is especially useful in connection with potassium permanganate [763, 764] or osmium tetroxide [765], Such mixed oxidants oxidize alkenes to carbonyl compounds or carboxylic acids, evidently by way of vicinal diols as intermediates. Sulfides are transformed by sodium periodate into sulfoxides [322, 323, 766, 767, 768, 769, 770, 771, 772], and selenides are converted into selenoxides [773]. Sodium periodate is also a reoxidant of lower valency ruthenium in oxidations with ruthenium tetroxide [567, 774],... 

The results of some oxidations with potassium permanganate differ depending on the pH of the reaction. For example, stearolic acid gives 9,10-diketostearic acid at pH 7-7.5 (achieved with carbon dioxide) and azelaic acid on treatment at pH 12 [864]. In some reactions, potassium permanganate is used as a catalyst for oxidation with other oxidants, such as sodium periodate. Thus alkenes are cleaved to carbonyl compounds or acids via vicinal diols obtained by hydroxylation with potassium permanganate, followed by cleavage by sodium periodate [763, 552]. 

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