Treating an alkene with cold, dilute KMnO4 yields which product?

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Multiple Choice

Treating an alkene with cold, dilute KMnO4 yields which product?

Cold, dilute KMnO4 adds across the carbon–carbon double bond in a syn fashion to give a vicinal diol. The oxidant forms a manganate ester intermediate that hydrolyzes to two hydroxyl groups attached to adjacent carbons, so the product is a diol. Because the conditions are mild, the double bond is hydroxylated rather than cleaved. If you heated the solution or used concentrated KMnO4, you’d get oxidative cleavage, yielding ketones or carboxylic acids instead. Epoxide formation isn’t the typical outcome under these conditions, as permanganate more readily yields diols with cold, dilute reagent.

Cold, dilute KMnO4 adds across the carbon–carbon double bond in a syn fashion to give a vicinal diol. The oxidant forms a manganate ester intermediate that hydrolyzes to two hydroxyl groups attached to adjacent carbons, so the product is a diol. Because the conditions are mild, the double bond is hydroxylated rather than cleaved. If you heated the solution or used concentrated KMnO4, you’d get oxidative cleavage, yielding ketones or carboxylic acids instead. Epoxide formation isn’t the typical outcome under these conditions, as permanganate more readily yields diols with cold, dilute reagent.

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