Alcohols ozonations, ketone synthesis, ozone

Ozone, while somewhat inconvenient to use, is way qiecific in its reactions with alkenes. It is widely employed for selective synthesis, for qualitative and quantitative analysis of unsaturated compounds, and for studying the position of double bonds in macromolecules. The nature of the products obtained from ozonolysis reactions is determitted by the way in which the reaction is carried out Different workup procedures (hydrolytic, reductive or oxidative) can be used to produce alcohols, aldehydes, ketones, carboxylic acids or esters. 

During the course of a synthesis of the steroid ouabain, a methylene cyclobutane was synthesized and treated with ozone followed by reductive workup with Me2S. In the event, the expected ketone was not obtained. Instead, the primary ozonide was fragmented via a Grob-like fragmentation initiated by the neighboring alcohol (eq63).9 ... 

The sjmthesis of (+)-chanoclavin I (582) has been achieved by a multistage route from the acetal (580) by way of the key intermediate (581) whose aliphatic double bond is readily cleaved by ozone. A third, convenient synthesis of the diterpenoid trachylo-bane (586) has been achieved by a reductive homoallylic cyclization. Reaction of the mesylate ester (583) with methylsulphinyl carbanion gives the ketone (584) and the alcohol (585). Oxidation of the crude product mixture with Jones reagent gave ketone (584) which can be reduced to trachylobane (586). ... 

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