Cyclopropanones oxidative cleavage

Alkyl substituted cyclopropanols and cyclopropanone hemiacetals 115,116a) aiso undergo oxidative cleavage when exposed to air or peroxides the initial products are hydroperoxides such as 148. In the case of l-methoxy-2,2-dimethylcyclopropanol, the reaction can be followed by observing the emission peaks in the NMR spectrum, and these CIDNP effects have enabled identification of radical intermediates.1154) With di-f-butylperoxylate (TBPO), the isomeric radicals 143 and 144 are formed and these may undergo a diverse number of further reactions as indicated by the complex product mixture given in Table 20. 

Cyclopropanols and therefore cyclopropanone hemiketals are particularly sensitive to oxidative cleavage. The latter undergo oxidative cleavage of the C(l>-C(2) bond leading for the most part, to jS-propionate radicals which then may undergo a variety of second-stage conversions, as summarized in Scheme 23. With air or peroxides, hydroperoxides (50) are formed (equation 29). 

The oxidation of cyclopropanone hemiacetals, e.g. 34, by copper(II) nitrate proceeded viacyclo-propanoxyl radicals to give 1,4-diesters.Ring cleavage of the initial radicals was followed by coupling of the 3-oxoalkyl radicals. 

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