Oxidizing agents peroxyacids

Destruction of the aromatic ring is the mam reaction in the oxidation of tetrafluoro-o phenyleiiediamine with lead tetraacetate by products are tetrafluorobenzotnazole and tetrafluorochinoxalme denvatives [92] (equation 85) Polyfluonnated benzylideneanilines are oxidized by peroxyacids to different products dependmg on reaction contitions at room temperature the benzylidene carbon is oxidized with the formation of peroxy bonds [93 94] (equation 86), whereas in refluxing agent, the azomethme bond is cleaved [93] (equation 86) Pentafluorobenzylidencanilme is oxidized by peroxyacetic acid in dichlo-romethane at room temperature to perfluorobenzoic acid in a 77% yield [93]... 

The two major characteristic oxidation processes of alkynes are their transformation to 1,2-dicarbonyl compounds and their cleavage reaction to carboxylic acids.710 The structure of the starting compounds has a decisive effect on the selectivity of oxidation. Since 1,2-dicarbonyl compounds proved to be intermediates in further oxidations, carefully controlled reaction conditions are often necessary to achieve selective synthesis. Certain oxidizing agents such as peroxyacids and ozone are nonselective oxidants. 

The epoxidation of an alkene is clearly an oxidation, since an oxygen atom is added. Peroxyacids are highly selective oxidizing agents. Some simple peroxyacids (sometimes called peracids) and their corresponding carboxylic acids are shown next. 

Peroxyacid (Section 12.7) An oxidizing agent having the general structure RCO3H. 

Another common oxidizing agent is sodium m-periodate (NaI04). Leonard used sodium periodate to oxidize methylphenyl sulfide to the sulfoxide in near-quantitative yield. l In that report, many methods were summarized for oxidizing sulfides, including nitric acid, hydrogen peroxide, chromic acid, ozone, peroxyacids. 

Esters can also be formed upon oxidation of ketones with a peroxyacid oxidizing agent (such as mCPBA or CF3CO3H). This Baeyer-Villiger oxidation is especially useful in the preparation of cyclic esters (called lactones) from cyclic ketones. 

Exercise 22-41 Write reasonable mechanisms for the different oxidation reactions of cyclooctatetraene with mercuric ethanoate in ethanoic acid, methanol, and water solutions. Notice that compounds of the type Hg(OR)2 appear to act in some cases as OR-donating agents and also that the oxide produced from cyclooctatetraene and peroxyacids (Section 15-11C) rearranges readily in the presence of acids to phenylethanal. 

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