Ruthenium tetroxide properties

The physical properties, preparation and reactions of ruthenium tetroxide have been reviewed by Lee and van den Engh, Rylander," Haines and Hetuy and Lange. A more vigorous oxidant than osmium tetroxide, its reaction with double bonds produces only cleavage products. " Under neutral conditions aldehydes are formed from unsaturated secondary carbons while carboxylic acids are obtained under alkaline or acidic conditions. For example, Shalon and Elliott" found that ruthenium tetroxide reacted with compound (11) to give the corresponding aldehyde under neutral conditions, but that a carboxylic acid was formed in acidic or alkaline solvents (equation 23). 

All operations should be done in th,e hood, because ruthenium tetroxide possesses an unpleasant ozone-lik smell. Commercially available ruthenium dioxide may differ in its properties, especially,in its reaction with sodium periodate, depending on the way it is prepared and on the content of water in its hydrated form [1207],... 

Osmium bears a close resemblance to ruthenium in many of its chemical properties in fact, in certain respects, such as the formation of tetroxides, these two elements are absolutely unique amongst the metals of the platinum group. 

Most of the metallic oxidants which have been used for the oxidation of ethers have been based on oxides of the transition metals chromium, manganese and ruthenium, the latter being of greatest synthetic importance. The first reported example of the application of ruthoiium tetroxide in the oxidation of ethers tqipeared over 30 years ago in 1958, although an indication of its reactivity towards ethers had been obt ed some years before. In a systematic study which revealed the powerful oxidizing properties of the reagent, Berkowitz and Rylander demonstrated the quantitative conversion of tetrahydrofuran and R-butyl ether into y-butyrolactone and butyl butyrate, respectively. Significantly, no overoxidation was observed. Apart f m an unsuccessful attempt to oxidize ethylene oxide, no fitter attempts were made by the authors to examine further the scope of this novel transformation. In a series of subsequent publications and a patent, Wolf and his coworkers went on to exploit the reaction in the preparation of aldosterone and relr steroids (equation 1). 

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