Diaryl selenide

By the interaction of selenium tetrachloride and benzene in the presence of aluminium chloride. Diaryl selenides and diaryl diselenides are formed as by-products. 

For the diaryl selenides, RaSe, a variety of methods of preparation is available ... 

In addition to method (1), mixed diaryl selenides may also be obtained ... 

Most of the simple diaryl selenides are liquids, combining with bromine to yield dibromides. The ditolyl-, benzyl- and dinaphthyl-compounds are solids. 

When diaryl selenides in carbon disulphide, carbon tetrachloride or chloroform solution are treated with bromine, direct addition occurs, yielding dibromides, R2SeBr2. In some cases the dichlorides have been obtained by direct chlorination, but they are usually isolated by the action of hydrochloric acid on the selenoxides or dinitrates. 

Dibenzyl selenide gives an iodide when allowed to react with iodine in chloroform solution. Dinitrates are formed when nitric acid (density 1 4) acts upon diaryl selenides or upon their dibromides. The dihalides have their halogen removed by moist silver oxide, the hydroxides resulting. When sodium hydroxide is used they are transformed to the oxides, R2SeO, which also result when diaryl selenides are oxidised by 46 perhydrol. ... 

Unsymmetrical diaryl sulfides (60 R = 2-NO2, 4-NO2, 2,4-(N02)2 R = H, 4-NMe2) were obtained in 80-97% yields from the reaction under PTC conditions of nitro-activated aryl halides with arenethiolates generated in situ from the reduction of the corresponding diaryl disulfides with aminoiminomethanesul-finic acid (61).192 Arylthiolates carrying electron-withdrawing substituents were not sufficiently reactive. The reaction could also be applied to the synthesis of diaryl selenides, but not of ditellurides. 

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. 

Selenides (selenoethers)and tellurides can be prepared via RSe and RTe species, and selenium and borohydride exchange resin followed by the halide give the selenoether. The La/l2-catalyzed reaction of diphenyl diselenide with primary alkyl iodides gave arylalkyl selenides, and Inl has been used with benzyl halides. Diaryl selenides (Ar—Se—AF) have been prepared by couphng aryl iodides with tin reagents (ArSeSnR3) with a palladium(O) catalyst. ... 

Aryl selenides (ArSeAr and ArSeAr ) can be prepared by similar methodology. Symmetrical diaryl selenides were prepared by the reaction of iodobenzene with diphenyl diselenide (PhSeSePh), in the presence of Mg and a copper catalyst. Aryl halides react with tin selenides (ArSeSnR3), with a copper catalyst, to give the diaryl selenide. OS I, 220 III, 86, 239, 667 V, 107, 474 VI, 558, 824. Also see, OS V, 977. 

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. 

In a similar way, the formation of diaryl selenides has been performed using Cul (10 mol %), neocuproine (10 mol %), andNaOr-Bu as the base in toluene from aryl iodides and phenylselenol. ... 

Se(VI) species are shielded compared with the structurally related Se(IV) analogues H2Se04 (6 = 1001 ppm) and H2Se03 (6 = 1300 ppm). The d ( Se) of hypervalent tetraarylselenium compounds are not significantly different compared with those of divalent diaryl selenides. 

Selenium di-imides (132) were formed in methylene chloride solution from selenium tetrachloride with t-butylamine or sulphonamides and also from selenium metal with anhydrous Chloramine-T. They were found to be efficient reagents for the allylic amination of alken and alkynes. The first examples of selenium imides (133) were synthesized from diaryl selenides and Chloramine-T, from... 

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