Under mild oxidation with KMnO4, which product is expected from an alkene?

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Multiple Choice

Under mild oxidation with KMnO4, which product is expected from an alkene?

Cold, dilute KMnO4 oxidizes alkenes by a syn dihydroxylation, adding one OH to each carbon of the double bond to give a vicinal diol. This happens because the permanganate adds across the C=C in a single, concerted step to form a cyclic manganate ester, which on workup yields two hydroxyl groups on adjacent carbons. Because the conditions are mild, the double bond is not cleaved; no carbonyl fragments appear. If the oxidant were hot or concentrated, cleavage could occur, producing ketones, aldehydes, or carboxylic acids depending on the substitution pattern, but under mild conditions the diol is the expected product.

Cold, dilute KMnO4 oxidizes alkenes by a syn dihydroxylation, adding one OH to each carbon of the double bond to give a vicinal diol. This happens because the permanganate adds across the C=C in a single, concerted step to form a cyclic manganate ester, which on workup yields two hydroxyl groups on adjacent carbons. Because the conditions are mild, the double bond is not cleaved; no carbonyl fragments appear. If the oxidant were hot or concentrated, cleavage could occur, producing ketones, aldehydes, or carboxylic acids depending on the substitution pattern, but under mild conditions the diol is the expected product.

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