Selenoxides selenium dioxide

Samarium(II) iodide, 46, 3 Sandmeyer reaction, 2, 7 Schiemann reaction, 5, 4 Schmidt reaction, 3, 8, 9 Selenium dioxide oxidation, 5, 8 24, 4 Seleno-Pummerer reaction, 40, 3 Selenoxide elimination, 44, 1 Shapiro reaction, 23, 3 39, 1 Silanes ... 

Keywords Asymmetric synthesis. Oxidation, Selenium dioxide, Selenoxides, Selenuranes, Selenonium salts, Selones... 

In addition to selenoxides and seleninic acids as oxidation agents, diethyl selenite (109) was reported as the first efficient oxygen transfer reagent. Namely, it was found [48] that diethyl selenite (109), easily prepared by the reaction of selenium dioxide with ethanol [54], is able to convert selected... 

The electrochemical oxidation of dibenzo(c,e)-l,2-diselenine 89 to its radical cation and further transformations have been described (Scheme 20) <1996JEC183>. In wet acetonitrile the oxidation has been shown to take place in two steps, the first an oxidation to the selenoxide followed by a further oxidation with extrusion of selenium dioxide to afford the corresponding selenophene <1992MI2077>. 

There are still other selenium-mediated oxidative transformations that do not depend on selenium dioxide. Thus, selenylation, oxidation, and selenoxide elimination constitute a valuable reaction sequence for introducing a,j0-unsaturation into a carbonyl compound, as... 

Treatment of the hydronitrates in aqueous solution with sodium carbonate causes evolution of carbon dioxide. Evaporation to dryness, followed by extraction with alcohol or benzene, then yields oils which are probably the selenoxides. These oils with concentrated hydrochloric acid are converted into white solids, crystallisable from benzene, xylene, alcohol or dry ether. These solids are the dichlorides of the original selenides, and when prepared by this method their melting-points are as follows Phenyl methyl selenium dichloride, M.pt. 122° C. phenyl ethyl selenium dichloride, M.pt. 64° to 65° C. diphenyl selenium dichloride, M.pt. 142° C. 

Lang and Comasseto have shown that formamidinesulfinic acid, or thiourea dioxide (6), is an efficient and inexpensive reagent for reducing selenoxides and telluroxides, as well as various selenium(IV) halide derivatives, to the corresponding selenides and tellurides. 

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