Azido-phenylselenenylations

Azido-phenylselenenylations of olefinic compounds can be effected with BAIB/PhSeSePh/NaN3 in CH2C12 (Scheme 14) [37]. Such additions proceed in anti-Markovnikov fashion and appear to be initiated by addition of the azido radical to the C,C-double bond. While cyclohexene and ds-4-octene gave 3 1 and 2 1 mixtures of diastereomeric adducts under these conditions, dihydropy-ran was converted cleanly to the trans-addition product. Regioselective azido-phenylselenenylations of dihydropyran derivatives and O-protected glycals with this reagent have also been documented [21,38,39]. 

The direct azido phenylselenenylation of alkenes can be accomplished by four different methods A126 reaction with phenylselenenyl chloride and sodium azide in dimethyl sulfoxide or dimethylformamide B127 reaction with diphenyldiselenide, sodium azide and iodosobenzene diacetate in dichloromethane C128 reaction with iV-phenylselenophthalimide (TV-PSP) and azidotrimethylsilane in dichloromethane D128 as in C but in the presence of 0.1 equivalent of tetrabutylammonium fluoride. 

Similarly, mphenylselenenyl bromide or methylselenenyl bromide, followed by sodium azide in trifluoromethanol or lithium azide in dimethylformamide 6 8. 

Azidoselenenylation of glycals 62 carried out with (diacetoxyiodo)benzene and sodium azide in the presence of diphenyl diselenide affords mixtures of 2-azido-2-deoxy-l-phenylselenenyl-glycosides 63A and 63B in a ratio between 1 1 and 1 389,99,, 0°. 

A mixture of 0.192 g (1 mmol) of phenylselenenyl chloride, 0.130 g (2 mmol) of sodium azide and 0.082 g (1 mmol) of cyclohexene in 5 mL of DMSO is stirred at r.t. overnight. Then 20 mL of ieri-butyl methyl ether are added and the solution is washed well with H20 and evaporated to give iram-2-azido-l-phcnylselcno-cyclohexane yield 91%. 

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See also in sourсe #XX -- [ ]

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