Glycol-cleavage, with periodic acid

However, regiopure azido 1,2-diol 19 is converted to the corresponding azido carboxylic acid 22 by oxidative glycol cleavage with periodic acid in the presence of catalytic amounts of ruthenium trichloride. Interestingly, the use of sodium periodate instead of periodic acid resulted in a 10-15 % epimerization of the C-5 stereocenter. 

Glycol cleavage with periodic acid or sodium metaperiodate, followed by reaction of the products to yield visible or fluorescent spots. 

Perchloric acid (79% HCIO4/CH2CI2, 0°, 1 h 25°, 3 h, 87% yield) and periodic acid (aq. dioxane, 3 h, quant, yield) cleave 1,3-dioxolanes the latter drives the reaction to completion by oxidation of the ethylene glycol that forms. Yields are substantially higher from cleavage with perchloric acid (3 AHCIO4/THF, 25°, 3 h, 80% yield) than with hydrochloric acid (HCl/HOAc, 65% yield)... 

Fig. 17.23. Mechanism of the glycol cleavage with NaI04 or H5I06, respectively. A diester of iodo(VII) acid (periodic acid) is formed initially. The ester decomposes in a one-step reaction in which three valence electron pairs are shifted simultaneously.

Sodium metaperiodate, NaI04, is a common, commercially available oxidant widely used in organic synthesis. As with periodic acid, sodium metaperiodate can be used for the glycol-cleavage oxidation reaction, which is particularly important in carbohydrate chemistry. Scheme 3.370 shows a representative example of a glycol-cleavage oxidation with NaI04 this reaction has been used in the synthesis of (25,45)-4-hydroxyproline... 

For in = 2, 3) H5IO5, ether, THF, 77-99% yield. This method also cleaves oxathioacetals, but did not affect the acid-sensitive acetonide or 1,3-diox-olane. Note that ethereal periodic acid has been used to cleave terminal acetonides with subsequent glycol cleavage. ... 

As to the first point, tartronic dialdehyde (8) could, as has already been suggested (32), be oxidized by classical glycol cleavage to give three molar equivalents of formic acid (and no carbon dioxide) with the concomitant reduction of two (instead of three for the enol form) molar equivalents of periodate ... 

Aqueous periodic acid can be used to achieve glycol cleavage, combined with anodic oxidation of the iodate, which is formed, back to periodate [70]. Oxidation of iodate is catalysed at a lead dioxide anode [71] but at the potentials required, aldehydes are oxidised to the corresponding acids. Due to this further reaction, the redox-mediated cleavage of diols to form an aldehyde may be difficult to achieve witli a catalytic amount of periodic acid. Cleavage using a stoichiometric amount of periodic acid, followed by recovery of the iodic acid and then its electochemical oxidation, has been achieved [72]. 

Vicinal diols (glycols) are easily cleaved under mild conditions and in good yield with NaI04 or H5I06. Mechanistically an intermediate diester of periodic acid is formed first. The successive cleavage of this intermediate 20 leads in an one-step process to the carbonyl 21 and the iodine(V) species 23. 

Vic-Glycol Content. This can be determined through use of the periodate cleavage technique. This methodology has been described earlier and with glycrophosphoserine, there will be 1 mol periodic acid consumed (per mole of... 

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