Alkene reaction with KMnO

Diols are oxidatively cleaved by reaction with periodic acid (HIO4) to yield carbonyl compounds, a reaction similar to the KMnO cleavage of aJkenes just discussed. The sequence of (1) alkene hydroxylation with OsO< j followed by (2) diol cleavage with HIO4 is often an excellent alternative to direct alkene cleavage with ozone or potassium permanganate. 

This reaction can be used to confirm whether or not a compound is an alkene. When an alkene is treated with cold, alkaline KMnO solution, the violet color of KMn04 solution disappears and turns brown. This is called Baeyer s reaction. 

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