Computational chemistry dioxiranes

In the past decade more efficient code and faster computers have allowed the use of electron-correlated methods of calculation and this has opened this area of theoretical chemistry to a wide range of research groups. The present sequel will be focused mainly on recent theoretical studies on a variety of oxidative processes involving oxygen atom transfer. We will include an extensive description of the very recent chemistry of peroxyni-trous acid (HO—ONO), dioxiranes, peracids and alkyl hydroperoxides. Since chemically realistic molecular systems can now be treated at an adequate level of electron-correlated... 

One mechanistic matter that has caused quite a bit of general consternation about a decade ago concerns the experimental evidence for the involvement of diradical intermediates (proposed as sources for the observed radical products) in dioxirane epoxidations, which were thought to be formed through induced peroxide-bond homolysis by the alkene. Nonetheless, rigorous experimental and high-level theoretical work disposed such radical chemistry in the epoxidation of alkenic substrates. The latter computations unequivocally confirm the established concerted mechanism, in which both CO single bonds in the incipient epoxide are concurrently formed by way of an asynchronous, spiro-structured transition state for the oxygen transfer. 

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