Conversion of Vicinal Diols into Dicarbonyl Compounds by Manganese Dioxide

The Oxidation of Organic Compounds by Active Manganese Dioxide

“…For example, dodecanedial, as the oxidation product of 1,2-cis-cyclododecanediol, is accompanied by 1,2-cyclododecanedione (14%) and traces of 2-hydroxycyclododecanone. 92 Several useful synthetic preparations of some otherwise difficulty accessible carbonyl compounds from 1,2-diols are summarized in Table VII Saturated aliphatic tt-hydroxyketones were readily oxidized with active manganese dioxide in refluxing organic solvents to the corresponding 1,2-diones in yields comparable to those given by other methods; for example, 3-hydroxyhexanone gave 3,4-hexanedione (52% yield) and 4-hydroxyoctanone was converted into 4,5-octanedione in 58 % yield J29 [Eqs. (10) and (II)].…”

“…46 o .y A striking example of a stereochemical preference in active manganese dioxide oxidation of the saturated alcohols (under mild conditions I has been reported by Ohloff and Giersch. 92 Thus, 9, lO-cis-decalindiol (50; and other vic-diols) is easily oxidized to dike tone 51 in 90% yield, whereas the 9, lO-trans isomer 52 (and other conformationally rigid diols with a dihedral angle of 180 0 subtended by the hydroxy groups) remains unaffected even on prolonged treatment with the reagent. 92 A stereochemical dependence was also observed in the terpene series.…”

“…92 Thus, 9, lO-cis-decalindiol (50; and other vic-diols) is easily oxidized to dike tone 51 in 90% yield, whereas the 9, lO-trans isomer 52 (and other conformationally rigid diols with a dihedral angle of 180 0 subtended by the hydroxy groups) remains unaffected even on prolonged treatment with the reagent. 92 A stereochemical dependence was also observed in the terpene series. Thus, treatment of a sesquiterpenoid furanopentasol (a cis-fused-ring diol 53) with manganese dioxide in chloroform gave cis-fused ketoaicohol 54 in 95% yield 93 ; oxidation of a second hydroxy group was apparently prevented by the steric arrangement of two of the rings.…”

“…Beginning, for example, from the ester 89 (ethyl 3-methoxybenzofuran-3-carboxylate), the aldehyde 91 (3-methoxybenzofuran-2-carbaldehyde) was obtained in 87% yield by manganese dioxide oxidation of the intermediate primary alcohol 90 In certain cases an IX,p-unsaturated alcohol on oxidation with active manganese dioxide has afforded a saturated cyclic keto-ether. For example, treatment of the sesquiterpene dimethyl shellolate (92) with the reagent produced a keto-ether (93); the reaction apparently proceeded by initial oxidation of 92 to an IX,p-unsaturated ketone, followed by ring closure via a Michael-type addition of the tertiary hydroxy group to the conjugated system. 141 In oxidation of a,{3-unsaturated diols or polyols with active manganese dioxide, several reactions are possible, involving one or more hydroxyl groups (depending on their degree of activation by multiple bonds); in general, the rate of oxidation is in the order primary> secondary> tertiary hydroxy groups.…”

Vanadium catalyzed aerobic carbon–carbon cleavage

“…Occasionally, other reagents such as chromium trioxide [32,33], manganese dioxide [34,35], iron(III) trisphenantrolines [36], calcium hypochlorite [37], pyridinium chlorochromate [38], N-iodosuccinimide, [39] have been also used.…”