Iron-catalysed reductive radical formation

Iron-catalysed reductive radical formation reactions have shown success toward olefin hydrofunctionalisation. Typically, procedures are general and operationally simple, allowing for rapid substrate derivatisation, both in simple and eomplex frameworks. 

Subsequently, Boger extended the established methodology to alkene hydrofluorination. Operating in a similar manner, following reductive radieal formation, the intermediate allq l radical species eould be trapped with a radieal fluorine souree ie. Selectfluor ). Similarly, Shen showed that alkenes eould be hydro-trifluoromethylthiolated using a radieal thiotri-fluoromethyl souree with borane as the required hydrogen souree.  

Baran reported an iron-eatalysed reductive alkene eoupling using phe-nylsilane as the hydrogen source. Using a simple proeedure, both inter-molecular reductive alkene coupling and intramolecular reductive cyclisation were possible. 

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Iron and copper catalyse the formation of oxyradicals. Three reactions are relevant in this context (1) Autoxidation of metal complexes may yield the superoxide radical which by itself is not very reactive, but is a precursor of more reactive radical species. (2) The one-electron reduction of hydrogen peroxide -the Fenton reaction - results in hydroxyl radicals via a higher oxidation state of iron [2]. (3) A similar reaction with organic peroxides leads to alkoxyl radicals, although a recent report alleges that hydroxyl radicals are also formed [3]. There is a fourth radical, the formation of which does not require mediation by a metal complex. This is the alkyldioxyl radical, ROO , which is formed at a... 

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