Dihydroxylation of olefins using osmate (VI) salts

A method of preparing a diol compound from an olefin, the method comprising oxidation of the olefin with an oxidant in the presence of a catalytic amount of an osmate (VI) salt in one or more solvent(s) at an elevated temperature,

• wherein the elevated temperature is in the range from 35° C. to reflux temperature of the one or more solvent(s),
• wherein the osmate (VI) salt has a general formula MjOsO4, MjOsO4·2H2O, or MjOsO2(OH)4, wherein M is a metal ion or ammonium ion, and j is 1 or 2,
• wherein the one or more solvent(s) comprises an alcohol selected from the group consisting of n-butanol, isobutanol, sec-butanol, amyl alcohol, iso-amyl alcohol, and mixtures thereof,
• wherein the oxidant is a tertiary amine N-oxide having a general formula R1R2R3N+—O−, wherein R1 is a C1-C10 alkyl, and R2 and R3 together with the N atom to which they are attached form a 5- to 7-membered heterocyclyl optionally containing 1 or 2 additional heteroatoms selected from O and N, and
• wherein the olefin is selected from the group consisting of cedrene, valencene, isopulegol, manool, sclareol, α and β-pinene, camphene, myrcene, ocimene, D-limonene, dipentene, squalene, (2E,4E)-hexa-2,4-diene, 6-Methyl-1,5-heptadiene, 2,6-dimethylhepta-1,5-diene, 1,5,9-cyclododecatriene, terpinolene, α-terpineol, β-terpineol, δ-terpineol, allyl alcohol, allyl chloride, β-citranellol, hydroxycitronellol, linalool, dehydrolinalool, geraniol, eugenol, β-fellandrene, α-thujene, Δ3-carene, nerolidol, trans-β-farnesene, dihydro farnesol, farnesol, homofarnesol β-caryophyllene, α-bisabolol, 2,4-Decadien-1-al, 1-acetylcyclohexene, Isofloriffone (1-[(1R,2S)-2,6,6-trimethylcyclohex-3-en-1-yl]ethanone), 6-Methyl-5-hepten-2-one, ethyl sorbate, and (Z)-hex-3-en-1-ol (leaf alcohol).