Permanganate peroxidation of cyclohexene. III. Hydroxide ion and salt effect studies

Abstract

. Good yields of cis-l,2-cyclohexanediol were formed by the reaction of cyclohexene and aqueous potassium permanganate under turbulent stirring conditions only in the presence of low concentrations of sodium hydroxide. Larger amounts had no further benefit or were deleterious. The lack of sensitivity to low concentrations of hydroxide ion indicated that its benefit is to inhibit acid promoted oxidations. There was no indication of its participation in the mechanism of glycol formation. The addition of the neutral salts, sodium sulfate or sodium nitrate, caused a decrease in glycol yields presumably due to a positive salt effect on a secondary negative ion -negative ion reaction, which formed other oxidation products. Stoichiometric amounts of hydroxide and potassium ions were not isolated as reaction products due to interaction with the hydrated manganese dioxide in a 1 : 2 ratio. The mechanisms in acidic and basic solutions appear to be quite different. A mechanism for basic solutions is suggested.JAY E. TAYLOR et RENEE GREEN. Can. J. Chem. 63, 2777Chem. 63, (1985. I1 se forme de bons rendements de cyclohexanediol-l,2-cis lors de la rtaction du cyclohexbne et du permanganate de potassium, soumis une agitation tumultueuse et seulement en presence de faibles concentrations d'hydroxyde de sodium. Des concentrations plus fortes d'hydroxyde n'amtliorent pas la reaction; elles peuvent m&me avoir un effet contraire. Le manque de sensibilitC 2 la presence de faibles concentrations d'ions hydroxydes indique que ces derniers inhibent les oxydations favorisees par les milieux acides. On n'a aucune preuve de leur participtation au mCcanisme de formation du glycol. L'addition de sels neutres, comme le sulfate de sodium ou le nitrate de sodium, provoque une diminution du rendement en glycol et cet effet est probablement cause par un effet de sel positif sur une reaction secondaire entre ions nCgatifs qui forme d'autres produits d'oxydation. A cause de l'interaction avec le dioxyde de manganbse hydrate, dans un rapport de 1 :2, on n'a pas is016 des produits de la riaction des quantites stoechiomCtriques d'ions potassium et hydroxyde. Les mkanismes de reaction en solutions acide et basique semblent &tre trbs difftrents. On suggbre un mecanisme pour les reactions en solutions basiques.[Traduit par le journal]

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

“…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 …”

Polyethylene-bound soluble recoverable palladium(0) catalysts

“…using Pd[P(C6H5)3]4 as a homogeneous catalyst is known to be useful in such reactions in which both carbon and heteroatom nucleophiles substitute for allylic carboxylate groups. 16 Yields and typical examples of this reaction are listed in Table I. In these reactions and in the other chemistry discussed below, 4 could be reused repeatedly so long as adventitious oxygen was excluded.…”