Permanganate peroxidation of cyclohexene.I. The unusual effect of turbulent stirring and dilution upon glycol yields

Abstract

(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 ...

Vicinal Dihydroxylation of Alkenes with Tetradecyltrimethylammonium permanganate and potassium hydroxide in a two phase Solvent System

“…[1][2][3] The yields of diols, however, are seldom above 50% though they can be improved with phase transfer catalysis [4][5][6] or by increased stirring. 7 The preparation and absorption spectrum of a stable solution of manganese (V) diesters by reacting alkenes with pulverised potassium permanganate in dichloromethane and benzyltriethylammonium chloride as a phase transfer agent has been reported 8,9 by Ogino and his group. It is probable that the intermediate manganate (V) diester is more stable under these conditions because it would be complexed with the quaternary ammonium ion and the hydrolysis reaction would be suppressed by the absence of water.…”

Aqueous Permanganate Oxidations of Cycloalkenes to cis-Glycols and Cis to Trans Conversions

“…(3) As the reaction proceeds and MnO 2 is formed, increased viscosity, clumping of the precipitate, and entrainment of the alkene result. More efficient stirring can, at least in part, offset these effects and can greatly increase glycol yields as was previously shown for cyclohexene. , …”

“…The preparation of cis -1,2-cyclohexanediol by permanganate oxidation of cyclohexene has been studied extensively, − and it was demonstrated that excellent yields <87% can be obtained by a turbulent stirring technique. A mechanism was also developed …”

Expeditious Racemic and Enantiodivergent Synthesis of 1‐Deoxymannojirimycin and 1,4‐Dideoxymannojirimycin

“…Known unsaturated lactam 8 , which can be prepared in a multigram scale,21 was chosen as the starting material for a cis hydroxylation to give racemic 4,5‐dihydroxylactam 9 . Among the various options for such a reaction, the addition of an aqueous solution of KMnO 4 to a vigorously stirred alkaline solution of the substrate in water at 0 °C worked best in terms of product recovery and yield after work‐up 22,23. Reagent concentrations, pH, and addition rate were critical to avoid either overoxidation or migration of the double bond to give the corresponding α,β‐unsaturated lactam.…”