Benzenesulfonyl bromide

Solvolysis of Benzenesulfonic Anhydride. Solvolysis of various arenesulfonic anhydrides in aqueous acetone revealed the reaction mechanism to be Sn2 in accord with established results for similar systems.  

Physical Data mp 19.5 °C bp 76-78 °C/0.17 mmHg. Solubility sol CH2CI2, Et20, THF, CeHe, MeCN. 

Preparative Method prepared by reaction of sodium benzene-sulfonate with bromine in 98% yield.  

Handling, Storage, and Precautions by analogy to benzenesulfonyl chloride, benzenesulfonyl bromide should be assumed to be an irritant and harmful by skin absorption and ingestion. Benzenesulfonyl bromide is best used immediately following preparation and may be used in situ. The reagent is moisture sensitive and will react with nucleophilic solvents (e.g. alcohols), liberating HBr and therefore should be stored under an inert atmosphere. Use in a fume hood. 

Addition to Unsaturated Compounds. Benzenesulfonyl bromide undergoes radical-mediated addition to alkenes and alkynes. Addition to alkenes leads to bromo sulfones, which undergo dehydrobromination to give vinyl sulfones (eq 3).  

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Several products are formed when phenylcyclopropane is irradiated in acetonitrile with added trifluoromethylsulfenyl chloride. The phenylpropane derivative (284) is one of the products and its formation can be rationalised by attack of a chlorine atom, formed by S-Cl bond fission, on the cyclopropane to yield the radical (285) which combines with a trifluoromethylthio radical to give the product. cw-Stereoselective addition of benzenesulfonyl bromide occurs to the tricycloheptane (286) on irradiation and the two products (287) and (288) are formed in a ratio of 3 1... 

A small amount of sodium benzenesulfinate was then added to react with the excess bromine. Filtration removed sodium bromide, and benzene was used to wash the filtrate (51 g. dry weight, 0.5 mole). Solvent was first removed from the filtered solution and combined washings on a rotary evaporator and finally by vacuum distillation. Vacuum distillation of the crude product (b.p. 76-78° at 0.17 mm.) gave 106.3 g. (92.2%) of benzenesulfonyl bromide.4... 

Many applications of benzenesulfonyl bromide are compatible with benzene as solvent. In such cases, isolation is unnecessary and it may be assumed that benzenesulfonyl bromide was formed quantitatively. For most uses there appears to be no real advantage in the final vacuum distillation. The procedure has the merit of simplicity and high yield and takes only a few minutes. 

Benzaldehyde, 100, 105, 154, 175, 336 Benzamide, 320 Benzene, 134, 154, 198, 286 Benzenesulfenyl chloride, 182 Benzenesulfinic acid sodium salt, 18 Benzenesulfonamide, 18 Benzenesulfonyl azide, 17—18 Benzenesulfonyl bromide, 18 Benzenesulfonyl chloride, 17 N-Benzenesulfonylformimidic acid ethyl ester, 18-19 Benzenethiol, 182 Benzhydrol, 238 Benzil, 312 Benzimidazole, 126 2,1-Benzisothiazole, 290 Benzobicyclo[2.2.2]octadiene, 46 Benzocyclobutadiene, 227 Benzohydroquinones, 60 Benzoic acid, 175... 

Reaction with Arenes. Benzenesulfonyl bromide reacts readily with trifluoromethanesulfonyl derivatives, yielding the corresponding mixed anhydrides (eq 6) which have been used to convert arenes to aryl phenyl sulfones under Friedel-Crafts-type conditions. 

Protection of Nitrogen Formation of Sulfonamides. Unlike the corresponding arenesulfonyl chlorides, benzenesulfonyl bromide has been used much less extensively in organic synthesis. Primary amines and imidazoles (eq 1) have been converted to the corresponding benzenesulfonamides and, with indoles, bromi-nation at C-3 occurs with concomitant sulfonamide formation (eq 2). ... 

In recent years, a variety of aryl boronic acids are commercially available, albeit in some cases they may be expensive for large scale purposes. During our work in the mid-1990 s boronic acid (II) was not commercially available and so two different protocols were used to prepare this acid. The first approach involved the transmetallation with n-butyl lithium of aryl bromide (I) and trapping the lithio species generated with trialkyl borate followed by an acid quench. Aryl bromide (I) is easily prepared by reaction of o-bromobenzenesulfonyl chloride with 2-propanol in the presence of pyridine as a base. The second approach was a directed metallation of isopropyl ester of benzene sulfonic acid (VII), to generate the same lithio species and reaction with trialkyl borate. The sulfonyl ester is prepared by reaction of 2-propanol with benzenesulfonyl chloride. From a long-term strategy the latter approach is... 

Acetyl bromide, 0728 f Acetyl chloride, 0735 f Aciyloyl chloride, 1093 Azidocarbonyl fluoride, 0339 Benzenesulfinyl chloride, 2234 Benzenesulfonyl chloride, 2235 Benzoyl chloride, 2675 Benzyl chloroformate, 2931... 

High-yield amination of aryl-, benzyl- and alkenyl magnesium bromides has been successful using l,3-dioxolan-2-one 0-(benzenesulfonyl)oxime 61 (Scheme 66) . 

Carbomagnesiation of alkenyllithium with allylmagnesium bromide gives rise to gem-bismetallic derivatives 5553. Chlorination of 55 with benzenesulfonyl chloride and treatment with alkyllithium (2 equiv) afford the alkylation product 57 in good overall yield (equation 31)54. A mechanism involving 1,2-migration of the formed intermediate zincate carbenoids 56 has been proposed for this reaction. 

The magnesium bromide salt of indole gives the 3-carboxy derivatives in about 30% yield on reaction with carbon dioxide (56JCS2853). Ethyl indole-3-carboxylate can be obtained directly, but in modest yield, using ethyl chloroformate (62JOC496, 6602805). Indole-2-carboxylic acid derivatives can be obtained via the benzenesulfonyl-protected 2-lithio derivative (equation 181) (73JOC3324). 

Acetyl bromide, 0724 f Acetyl chloride, 0731 f Acryloyl chloride, 1090 Azidocarbonyl fluoride, 0338 Benzenesulfinyl chloride, 2227 Benzenesulfonyl chloride, 2228 Benzoyl chloride, 2671... 

Activation of the oxime with benzenesulfonyl chloride or p-toluenesulfonyl chloride leads to sulfonate esters which undergo the Beckmann reaction with or without isolation. - The sulfonate esters also rearrange under mild reaction conditions on silica gel.i Under neutral conditions, lV,A(-carbonyldiimida-zole activates oximes in the presence of allyl bromide, followed by spontaneous Beckmann rearrangement. ... 

Cyclopropane with two geminal benzenesulfonyl groups as activating functions as in 3 reacted with benzenethiolate with ring opening. The carbanion formed as an intermediate could be trapped by alkyl halides such as iodomethane and allyl bromide. ... 

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