Organic Process Research & Development 1998, 2, 147−150
Aqueous Permanganate Oxidations of Cycloalkenes to cis-Glycols and Cis to Trans Conversions Jay E. Taylor,*,† Thomas E. Janini, and Otto C. Elmer Department of Chemistry, Kent State UniVersity, Kent, Ohio 44242
Abstract: A series of cis-glycols including 1,2-cyclopentanediol, 1-methyl1,2-cyclopentanediol, 1,2-dimethyl-1,2-cyclopentanediol, 1,2cyclohexanediol, 1-methyl-1,2-cyclohexanediol, 1,2-dimethyl-1,2cyclohexanediol, 1,2-cycloheptanediol, 1,2-cyclooctanediol, exo,exobicyclo[2.2.1]heptane-2,3-diol, and bicyclo[2.2.2]octane-2,3-diol have been prepared by permanganate oxidations of cycloalkenes using a turbulent stirring technique. Conditions for the reactions, methods of purification, and yields are presented. Both hydroxide ion and an aqueous environment are highly essential to the formation of glycols. Excessive solvent decreases yields. A procedure for converting certain cis- to trans-glycols is given. A preparation for very pure ∆9,10-octalin is included.
Table 1. cis-Glycol yields from various cycloalkenesa alkene cyclopentene 1-methylcyclopentene 1,2-dimethylcyclopentene cyclohexene 1-methylcyclohexene 1,2-dimethylcyclohexene cycloheptene cyclooctene bicyclo[2.2.1]heptene bicyclo[2.2.2]octene ∆9,10-octalin
% % yield CH3OH 64 64 50 87 64 40 50 50 63b 46c 0
15 40 40 25 10 40 50 50 30 40
°C 0 -20 -20 14 5 -10 20-35 38 0 5
reactant, final mol vol, L 1.0 16.0 0.19 1.85 0.21 2.0 0.385 4.0 0.18 1.5 0.17 2.1 0.5 4.5 0.2 3.5 0.3 2.3 0.009 2.3 various
a Yields were calculated according to the percent purity of the alkene. The cis-glycol products were 99% pure or better after the indicated purification. The glycol yields represent isolated product. b Hexane (50 mL) was added to solubilize the solid alkene. c Toluene (10 mL) was added to solubilize the solid alkene.
Introduction The preparation of cis-1,2-cyclohexanediol by permanganate oxidation of cyclohexene has been studied extensively,1-3 and it was demonstrated that excellent yields
