Alcohols, secondary, oxidation with sodium bromate

Although NaI04 or KI04 are the secondary oxidants used in the vast majority of cases in which alcohols are oxidized with catalytic Ru04, the employment of sodium hypochlorite (NaOCl),31 sodium bromate (NaBrOj )32 or Cl+, electrolytic-ally generated by oxidation of chloride ion,33 have also been reported. 

Cerium (TV) ammonium nitrate (CAN)37 and a cerium (TV) impregnated resin38 are able to catalyze the selective oxidation of secondary alcohols with sodium bromate (NaBrOi). Stoichiometric cerium bromate— CelBrCb h, prepared in situ from barium bromate and cerium (III) sulfate, is also able to perform selective oxidations of secondary alcohols.39... 

Ammonium cerium(IV) nitrate or cerium(IV) sulfate will catalyze the selective oxidation of secondaiy alcohols with sodium bromate as cooxidant, in this case remote C—C double bonds interfere, but 1,2-diols are not cleaved. It has been found that sodium bromite in aqueous acetic acid will act as a selective oxidant for secondary mary diols without the need for other catalysts (Scheme 21). ... 

Ceric ammonium nitrate or ceric sulfate is used to oxidize saturated and unsaturated secondary alcohols to ketones. The ceric salts are used only in catalytic amounts with sodium bromate as a reoxidant (equation 241) [741]. 

A very efficient method for the oxidation of secondary alcohols to ketones makes use of sodium bromate in the presence of ruthenium dioxide. Quantitative yields are obtained in 15 min at 25°C. Pulsed irradiation, with a 20% duty cycle, was used in addition to stirring. It appears that the sonochemical rate increase is due to two factors the acceleration of the oxidation of ruthenium dioxide to the actual reactive species ruthenium tetroxide, and the very efficient ultrasonic emulsification of the biphasic carbon tetrachloride-water system. 

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See also in sourсe #XX -- [ ]

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