Cyclohexene reacts with cold, dilute, alkaline $\mathrm{KMnO}{}_4$. The major product is

Cold dilute permanganate adds two OH groups to the same face of the double bond through a cyclic manganate(V) ester (syn dihydroxylation). The product is cis-1,2-cyclohexanediol. Hexanedioic acid forms only under hot, concentrated conditions.