Oxidative Cleavage of 1,2-Diols
Oxidative Cleavage of Vicinal Diols with Periodic Acid: Stereochemistry
The ability of the diol to to form an intermediate cyclic diester with periodic acid is critical for the succesful cleavage of vicinal diols. Cis- as well as trans-1,2-cyclohexanediol can form such an intermediate.
Conformationally fixed trans diols cannot form cyclic diesters. Therefore, the reaction does not lead to diketones.
However, bond cleavage can be effected with lead tetraacetate as the oxidizing agent even though formation of the intermediate cyclic diester with lead(IV) acid is not possible. In this case, the lead tetraacetate cleavage of glycols can be explained by invoking a second mechanism that involves the intermediacy of a monoester of lead(IV) acid.
Naturally, the reaction is slower when compared to the analogous cleavage of cis glycols because these can form the favored cyclic intermediate.