ISSN:
0570-0833
Keywords:
Oxygen transfer
;
Peroxides
;
Reaction mechanisms
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In this progress report an attempt is made to rationalize, from a mechanistic point of view, the different ways in which oxygen is transferred from inorganic and organic peroxides to nucleophilic substrates, particularly olefins. Oxygen transfer from transition-metal peroxides, which is relevant to catalytic oxidations using O2, H2O2 or ROOH, occurs via a cyclic or “pseudocyclic” peroxymetalation in which a dioxametallacycle is formed. Owing to the wide discrepancy between peroxymetalation and the conventional oxidation mechanism, i.e. nucleophilic attack of the substrate at the electrophilic “active oxygen”, we propose an alternative mechanism involving dioxiranes as the reactive species. The generation of dioxiranes appears to be a common denominator in the reactions of most organic peroxides e.g. peroxy acids, the reaction of electrophilic ketones with H2O2, or ozonizations. Oxygen transfer from dioxirane reagents probably involves the formation of a charge-transfer π-complex between the substrate and the carbon atom of the dioxirane, and the subsequent formation of a cyclic peroxidic intermediate.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/anie.198207341
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