Selenoxide, benzyl phenyl

Sodium periodate is also frequently used as an oxidant for selenides, the reaction proceeds slowly in aqueous methanol. Various selenoxides such as methyl phenyl and benzyl phenyl selenoxides, (3B), (39),2 (40) and 2-azidocyclohexyl phenyl selenoxide have been isolated in this way. Other solvents and reaction conditions may also be employed. " °... 

The isolable and thermally stable selenoxides are, therefore, rather limited. Stable examples are as follows those derived from selenides which have no hydrogen atoms on the -carbon, such as dimethyl sel-enide, aryl methyl selenides, diaryl selenides and benzyl phenyl selenides, those with an intramolecular hydrogen bonding, such as (36) and (37), and those leading to an unfavorable double bond such as (38). Vinylic selenoxides (39) and (40) are also generally isolable. 

Diphenyl selenide is oxidized with peroxyacetic acid at room temperature to diphenyl selenoxide hydrate, C6H5Se(OH)2, in 43% yield after 2 h [1198]. Benzyl phenyl selenide is oxidized to benzyl phenyl selenoxide by sodium periodate in aqueous methanol at 0 °C in 95% yield and by iodobenzene dichloride in aqueous pyridine at -40 °C in 85% yield [773]. 

Benzyl phenyl selenide allowed to react at 0 with a slight excess of Na-meta-periodate in methanol-water -> benzyl phenyl selenoxide. Y 95%. - lodobenzene dichloride can be used in cases in whidi periodate is not effective sudi as diaryl selenides with electron-withdrawing groups. F. e. s. M. Cinquini, S. Colonna, and R. Giovini, Chem. Ind. 1969, 1737. 

An ethanolic soln. of benzyl bromide and Na-phenylselenide refluxed 2 hrs. -> benzyl phenyl selenide (Y almost 100%) treated with Li-diisopropylamide and ethyl bromide in tetrahydrofuran, the resulting crude mixture treated with 30%-H2O2, and the product isolated after 24 hrs. -> product. Overall Y 80%. F. e. s. R. H. Mitchell, Chem. Commun. 1974, 990 syntheses of ethylene derivs. via a-metalation of selenoxides cf. H. J. Reich and S. K. Shah, Am. Soc. 97, 3250 (1975). 

Singlet oxygen (air, visible light and sensitizer) and benzyl phenyl selenide [which may be oxidized by O2 to the selenoxide, which may in turn oxidize Os(VI) back to... 

Iodine-catalysed hydroperoxidation of cyclic and acyclic ketones with aqueous hydrogen peroxide in acetonitrile is an efficient and eco-friendly method for the synthesis of gem -dihydroperoxides and the reaction is conducted in a neutral medium with a readily available low-cost oxidant and catalyst.218 Aryl benzyl selenoxides, particularly benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide, are excellent catalysts for the epoxidation of alkenes and Baeyer-Villiger oxidation of aldehydes and ketones with hydrogen peroxide.219 Efficient, eco-friendly, and selective oxidation of secondary alcohols is achieved with hydrogen peroxide using aqueous hydrogen bromide as a catalyst. Other peroxides such as i-butyl hydroperoxide (TBHP), sodium... 

The selenoxide 107 as well as its benzyl (3 = 890) and phenyl analogues (3 = 879) were separated into the enantiomers and their chiroptical properties investigated intramolecular nitrogen coordination stabilizes the selenoxide so that no bulky substituents were required Another selenoxide with N-stabilization is 108 ... 

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