Oxygen atom transfer peroxo bond

Early studies of these complexes focused primarily on the investigation of their oxygen-atom-transfer reactivity. Relatively little success was achieved, however. The peroxo fragments in these complexes exhibit nucleophilic character, and, therefore, they are generally ineffective oxidants for reactions with synthetically interesting electron-rich substrates such as alkenes and sulfides. Most of the known reactivity involves electrophilic substrates that, in many cases, insert into the Pd-0 bond of peroxopalladium(II) species (Fig. 4) [105,118]. 

Imido and 0x0 compounds are intermediates in many of the transfers of oxygen atoms and nitrene units to olefins to form epoxides and aziridines, and they are intermediates in many of the insertions of oxygen atoms and nitrene units into the C-H bonds of hydrocarbons to form alcohols and amine derivatives. The enantioselective epoxidation of allylic alcohols (Scheme 13.22) " is the most widely used epoxida-tion process, and the discovery and development of this process was one of the sets of chemistry that led K. Barry Sharpless to receive the Nobel Prize in Chemistry in 2001. The mechanism of this process is not well established, despite the long time since its discovery and development. Nevertheless, most people accept that transfer of the oxygen atom occurs from a titanium-peroxo complex - rather than from an 0x0 complex. Jacobsen s and Katsuki s - manganese-salen catalysts for the enantioselective epoxidations of unfunctionalized olefins, which were based on Kochi s achiral chromium- and manganese-salen complexes, are a second set of... 

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