1,2,3-Triols, periodate oxidation

Buchanan, Dekker and Long used periodate oxidation, followed either by Schiff s reagent (for cis-diols) or potassium iodide (for triols). The test is general for non-reducing carbohydrates having the necessary configuration of hydroxyls. Lead tetraacetate oxidation requires no further reagent to reveal the spot.66... 

Addition to 1-atkenes (8, 25). The critical steps in a recent synthesis of aldosterone (4) involve anli-Markovnikov addition of C6H5SeBr to I, oxidation to the allylic bromide, and acetate displacement to give 2. The corresponding 21-monoacctate was converted to the triol 3 (0s04, N-mcthylmorpholine N-oxide). The final steps to 4 involved periodate cleavage and saponification.2... 

The formation of diol-periodate esters is supported by physical evidence. The addition of ethane-1,2-diol to periodate solutions causes an initial rapid change in the uv absorption spectrum, followed by a slower change as the oxidation proceeds and lOJ is formed. Similar results are observed for other 1,2-diols except for highly substituted diols such as pinacol (Buist et al ). Buist and Bunton have shown that the cyclic periodate esters formed in alkaline solution from 1,2-diols and periodate can be detected by nmr. The initial fall in pH which occurs in the oxidations of ethane-1,2-diol and lightly substituted diols is also attributed to ester formation (Malaprade, Buist and Bunton ). Cyclic triesters, similar to the cyclic diesters formed from 1,2-diols, are formed from cyclic compounds containing the cis-l,2,3-triol system (Barker and Shaw , Dijkstra and from 1,2-0-isopropylidene-a-D-glucofuranose. In the latter case the presence of the triester has been demonstrated by nmr (Berlin and van Rudloff ). Monoesters of periodic acid have not been detected in any system, but they are postulated as intermediates in the formation of cyclic diesters from 1,2-diols (section 1.3.5). 

Angyal and Young report second-order kinetics for the oxidation of the camphane-2,3-diols. The cis- isomers are oxidised much more rapidly than the trans- isomers, and a temperature of 80 °C had to be used for kinetic measurements on the latter. It seems likely that the rigidity of the camphane skeleton prevents the formation of a cyclic diol-periodate ester from the trans- isomers. Possibly the reaction at 80° is completely different in nature from the normal oxidation of 1,2-diols by periodate. The same workers report that cholestane-3j8,6j8,7a-triol, in which the and 7a hydroxyl groups are axial-axial, is inert towards periodate. 

A solution of 1 g. of cholesterol a-oxide in 30 ml. of hot acetone is treated with a solution of 0.625 g. of periodic acid dihydrate in 10 ml. of water." Before all the precipitated oxide has redissolved, thin plates of cholestane-3/3, 5a,6(8-triol begin to separate. The mixture is refluxed for one half hour, cooled, and the product collected yield 0.83 g. (81%), m.p. 231-232°. A second crop of material (0.14 g.) melted at 225-226°. 

The rate of production of formic acid by periodate from triol groups has been used in determining the structure of the glycosidically bound trisaccharide solanose. Oxidation and other evidence suggested that the sugar moiety is either trisaccharide (3) or (4). 

Reduction of hydroxylycoctonine with sodium borohydride produced the triol VIII, explained as occurring by the reduction of VII after loss of water 12). Oxidation of VIII with periodic acid gave the hemiacetal ketone IX which was then converted to the unsaturated acetate X. While there is no rigorous proof of the configuration of the C-7 hydroxyl... 

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