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Oxidative Cleavage of 1,2-Diols

Oxidative Cleavage of Vicinal Diols with Periodic Acid: Mechanism

In this reaction, an intermediate cyclic ester is formed between periodic acid and the glycol derivative and water is eliminated concurrently. Presumably, the ester dissociates via an aromatic 6-electron-5-center transition state into two carbonyl fragments and iodic acid. Iodine is reduced from +VII to +V.

Fig.1
Mechanism of oxidative glycol cleavage
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Fig.2
3D model of periodate adduct
Comment
Lead tetraacetate reacts analogously. Unlike the periodic acid oxidation, the reaction with lead tetraacetate also takes place in non-aqueous media. The reaction proceeds via a five-membered lead alkoxy intermediate similar to the one observed in the periodic acid oxidation.

2D animation: Oxidative diol cleavage

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