2.4- Dinitrobenzenesulfenyl bromide

Dinitrobenzenesulfenyl bromide may be similarly prepared by refluxing 2,4-dinitrophenyl benzyl sulfide with the equivalent amount of bromine in 5 parts of dry carbon tetrachloride. As it is less stable than the chloride, losing bromine if overheated, it should be concentrated on a 40° water bath under vacuum. When worked up in the same manner as the chloride, the product usually contains some is-(2,4r-dinitrophenyl) disulfide. Because the disulfide is insoluble in carbon tetrachloride, the sulfenyl bromide may be readily purified by recrystallization yield 75-80%, m.p. 102-104°. 

The nature of the halogen bonded to the sulfenyl sulfur atom does not affect the stereochemical course of the addition. For example, the reaction of 2,4-dinitrobenzenesulfenyl bromide with (Z)- and (F )-2-butenes gives the products 4 of anfz-stereoselective addition168. 

Similarly, norbornene reacts with 2,4-dinitrobenzenesulfenyl bromide to give the trans-adduct trans-521. 

Alcohols p-Bromophenacyl bromide. 2,4-Dinitrobenzenesulfenyl chloride. 3,5-Dinitro-benzoyl chloride. o-Naphthylisocyanate. 4 -Nitroazobenzene.4<arboxylic acid chloride. p-Phenylazobenzoyl chloride. p-Phenylsulfonylbenzoyl chloride. p-Propionylisocyanate. 

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