Oxidative Cleavage of Vicinal Diols

Vicinal diols are cleaved by periodic acid to yield aldehydes or ketones, depending on the number of substituents on the carbon atoms bearing the hydroxyl groups. The periodic acid is reduced to 

If the vicinal diol is contained in an acychc portion of a molecule, two carbonyl compounds result—unless the vicinal diol is a symmetrical molecule, in which case it yields two equivalents of a carbonyl compound. If the two hydroxyl groups are on a ring, a ring-opened product containing two carbonyl groups forms. 

The cleavage reaction occurs by way of a cyclic periodate intermediate, which may formally be considered a diester of an inorganic acid. The cyclic ester forms more easily for cis diols than for trans diols, so the rate of cleavage of cis diols is faster than the rate of cleavage of trans diols. 

Reaction of the following diol with sulfuric acid yields a ketone with the molecular formula CioHigO Write the structure of the product 

A compound with the formula C12H22O2 reacts with periodic acid to give cyclohexanone. Write the structure of the reactant. 

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). 

Vicinal diol Periodic acid Aldehyde or ketone Aldehyde or ketone Iodic acid Water 

This reaction occurs only when the hydroxyl groups are on adjacent carbons. 

What is the oxidation state of iodine in Hi04 in HiOa  

Can you remember what reaction of an alkene would give the same products as the periodic acid cleavage shown here  

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The reaction is based, on the one hand, on the oxidative cleavage of vicinal diols by lead(IV) acetate and, on the other hand, on the reaction of dichlorofluorescein with lead(IV) acetate to yield a nonfluorescent oxidation product. The dichlorofluorescein only maintains its fluorescence in the chromatogram zones where the lead(IV) acetate has been consumed by the glycol cleavage reaction [1],... 

Recently, heterogeneous catalytic systems were described41 that employ molecular oxygen for the liquid phase oxidative cleavage of vicinal diols. Although the catalysts appear to be mixed metal oxides rather than supported metals the method resembles closely the noble metal-catalyzed oxidations described above, hence their inclusion in this section. 

Another reaction of practical interest is the oxidative cleavage of vicinal diols (reaction 17) that is traditionally achieved using the stoichiometric oxidants, periodates or lead tetraacetate. 

Oxidative Cleavage of Vicinal Diols in the Carbon Framework... 

Felthouse, T.R., Catatytic Oxidative Cleavage of Vicinal Diols and Related Oxidations by Ruthenium Pyrochlore Oxides New Catal3 ts for Low-Temperature Oxidations with Molecular Oxygen, J. Am. Chem. Soc. 109 7566-7568 (1987). 

The second method of enzyme electrode preparation is based on the immobilization of glycoenzymes via their glycosidic component [178]. Here the carbohydrate moiety of glycoenzymes is activated by a periodate oxidation cleavage of vicinal diols of the carbohydrate units. The... 

Polystyrene-based immobilized ruthenium catalysts can be used in oxidation of alcohols with NMO, TEMPO/O2, or O2 [94]. Catalytic oxidative cleavage of vicinal diols to aldehydes with dioxygen was reported with RuCl2(PPh3)3 on active carbon [95]. Ionic liquids such as tetramethyl ammonium hydroxide and Aliquat 336 can be used as the solvent for the RuCl2(PPh3)3-catalyzed aerobic oxidation of alcohols [96]. 

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. 

The reactions of the saccharides are characteristic of carbonyl, alcohol, and hemiacetal groups. They include oxidation of the aldehyde to the carboxy function of aldonic acifls, double oxidation to aldaric acids, oxidative cleavage of vicinal diol units, reduction to alflitols, condensations,... 

For the same reasons as described for the ozonolysis of alkenes, the oxidative cleavage of vicinal diols by periodate is hmited as a synthetic method. The vicinal diol is seldom directly available, and it must be prepared from an aUtene. We also recall that the hydroxyl groups must be located in a cis configuration, or the molecule must have sufficient conformational freedom to bring the two hydroxyl groups into a gauche conformation. The vicinal diol is prepared from an alkene by oxidation with osmium tetroxide. 

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