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(1984).Yields of cis-l,2-cyclohexanediol formed by the reaction of methanol-water solutions of potassium permanganate with cyclohexene varied from nearly zero to a high of 84% as a function of stirring efficiency and dilution. This unusual effect is attributed to the formation of an intermediate hypomanganate ester ion which after formation may undergo reaction [ I ] with water to form the glycol or [2] with excess Mn04-to form higher oxidation products. The factor of increased stirring and dilution reduced localized excess of Mn04-and, thereby, minimized the contribution of reaction [2]. Addition of modest concentrations of methanol increased the yield, and this is attributed to enhanced solubilization and dispersion of the insoluble cyclohexene. Sodium hydroxide was beneficial to the reaction but only in low concentrations.JAY E. TAYLOR, DAVID WILLIAMS, KENNETH EDWARDS, DONALD OTONNAA et DAVID SAMANICH. Can. J. Chem. 62, 11 (1984).Les rendements en cyclohexanediol-l,2-cis form6 lors de la reaction du cyclohexkne avec du permanganate de potassium dans des solutions aqueuses de methanol varient de 0 a prks de 84% en fonction de I'efficacitC de I'agitation et de la dilution. On attribue cet effect inhabituel a la formation d'un intermediaire, un ion hypomanganique, qui apres sa formation, peut subir soit la reaction [I] avec l'eau conduisant au glycol, soit la rCaction [2] avec un excks de Mn04-pour former des produits plus oxydts. L'effet combine d'une meilleure agitation et d'une plus grande dilution rCduit la prCsence IocalisCe d'excks d e Mn04-et diminuent ainsi la contribution de la rCaction [2]. L'addition de faibles quantitCs de methanol augmente le rendement; on attribue ce rCsultat une meilleure solubilisation et une plus grande dispersion du cyclohexkne qui est insoluble. L'addition d'hydroxyde de sodium est bCnCfique a la rCaction mais uniquement a de faibles concentrations. [Traduit par le journal]The conversion of cyclic alkenes to stereospecific glycols has been the subject of a number of investigations. Whereas performic acid quite generally gives good yields (60-90%) of trans-glycols (1) and is both easy to use and applicable to a wide variety of alkenes, the various reagents which have been used for the preparation of cis-glycols are each beset with serious disadvantages. Osmium tetroxide (2) and thallium acetate (3) are costly and poisonous and the procedures are quite involved. The iodine -silver acetate procedure (4) has been reported not to be dependably stereospecific (5) and is expensive for larger preparations as is the iodine -potassium iodate technique (6).Potassium permanganate solutions (7, 8) have been used alone and with a variety of additives including sodium hydroxide, magnesium sulfate, acetone, various alcohols, and phase transfer reagents. Potassium permanganate solubilized in anhydrous dichloromethane has been reported to give good yields with several more complex alkenes (9), but other permanganate procedures have generally been characterized by yields often under 50% and ...