REACTIONS OF 2,2'-DISELENOBIS(N-ALKYLBENZAMIDES) WITH PEROXIDES - A FREE-RADICAL SYNTHESIS OF EBSELEN AND RELATED ANALOGS

N-Alkyl-2-triphenylstannylbenzamides (3, R = Hex Ph, iso-Pro, tert-Bu) , prepared from the corresponding 2-benzylselenobenzamides, react with benzoyl peroxide in benzene, under reflux to afford the 2,2'-diseleno bis(N-alkylbenzamides) (4) in 54-87% yield Further treatment with benz oyl peroxide or di-tert-butyl peroxide in benzene or chlorobenzene aff ords the N-alkyl-1,2-benzisoselenazol-3(2H)-ones (2) in 76-82% yield. This transformation presumably involves intermediate amidyl radicals w hich undergo intramolecular homolytic substitution at selenium to affo rd the product.