Sulfonation of arenes

Of these the most important are the sulfonic acids In general however sulfonic acids are not prepared by oxidation of thiols Arenesulfomc acids (ArS03H) for example are prepared by sulfonation of arenes (Section 12 4)... 

It has been known472 that sulfones are side-products in the course of sulfonation of arenes with sulfur trioxide or its derivatives. Generally, this reaction may be expressed by equation 90. Mechanistic investigations have indicated473 that this reaction follows the pathway shown in equation 91. 

Succinic acid, 343 Succinic anhydride, 450 Sulfamic acid, 415 Sulfanilamide, 421 Sulfanilic acid, 415 Sulfonates, 263 Sulfonation of arenes, 207 Sulfhydryl group, 267 Sulfides, 294 Sulfones, 296... 

Yosida et al. [41] found that p-t< rr-butylcalix[6]ar-ene can extract Cu from the alkaline-ammonia solution to the organic solvent. Nagasaki and Shinkai [42] described the synthesis of carboxyl, derivatives of calix-[n]arenes ( = 4 and 6) and their selective extraction capacity of transition metal cations from aqueous phase to the organic phase. Gutsche and Nam [43] have synthesized various substituted calix[n]arenes and examined the complexes of the p-bromo benzene sulfonate of p-(2-aminoethyl)calix[4]arene with Ni, Cu , Co-, and Fe. ... 

E The writing has again been revised at the sentence level, streamlining the presentation, improving explanations, and updating a thousand small details. Several little-used reactions have been deleted (the alkali fusion of arene-sulfonic acids to give phenols, for instance), and a few new ones have been added (the Sharpless enantioselective epoxidation of alkene.s, for instance). 

Although anaerobic desulfonation of arene sulfonates, in which the sulfonate is used as a source of sulfur, has been described in a Clostridium sp., the product was not identified (Denger et al. 1996,... 

In the case of sulfonylation (Scheme 10) [56] and sulfinylation reactions [34], Bi salts proved again to be efficient catalysts. In contrast to the arylsulfonylation, which is under partial control of triflic acid, depending on the substrates, a complete synergistic effect between triflic acid and Bi chloride has been found in the alkanesulfonylation of arenes. In this case, the formation of mixed triflic/alkane-sulfonic anhydrides leads to the active electrophilic species. The formation of the latter exclusively requires the transient formation of a Bi chlorobistriflate species that acts as an intermediate shuttle for triflic acid, leading to the formation of the mixed anhydride precited (Scheme 11). Our experiments have shown that triflic... 

Sigmatropic Rearrangements Section 22.8 Sulfonation of an Arene Section 17.6... 

The direct functionalization of arenes by primary alcohol sulfonate esters has also been reported.44 5mol% AUCI3/AgOTf was again used as catalyst and high yields (up to 92%) of products obtained in some cases. Higher yields (e.g. 97, 93%) were obtained in intramolecular cycloalkylation reactions of a similar type. 

The facility of arene reductive elimination underpins numerous C-C, C-O and C-N bond-forming reactions, which may be catalysed by late transition metals, in particular palladium (Figure 4.10). Although there are many variants, the general reaction scheme involves introduction of the aryl in electrophilic form via oxidative addition of an aryl halide (or sulfonate), substitution of the palladium halide by a nucleophile (which may also be carbon based) followed by reductive elimination. It is noteworthy that nucleophilic aromatic substitution in the absence of such catalysts can be difficult. 

In the coupling of more challenging substrates, reduction of the aryl halide is frequently observed [21]. Specifically, in the reaction of electron-rich aryl halides or sulfonates, reduced arene is a major by-product. Presumably, this side-product arises when the palladium amide can undergo /1-hydride elimination to generate an imine and a palladium (II) aryl hydride (Scheme 2). Subse-... 

Much of the research on the SbCls-catalyzed halogenation of arenes has focused on the chlorination and bromination of perfluoroalkyl-substituted aromatics [14]. The reaction of organic disulfides with electron-rich aromatic compounds under catalysis with SbCls and AgSbFg affords unsymmetrical aryl sulfides in modest yields [15a]. Electrophilic sulfinylation and sulfonation can be similarly effected by SbCls [15a-c]. Alkyl- and halobenzenes give thiocyano derivatives when treated with a mixture of SbCls and Pb(SCN)2 in CCI4 [16],... 

Sulfonylation. Heating mixtures of arenes and arenesulfonyl chlorides generates diaryl sulfones. 

Benzene rings with substituents other than halo, nitro, sulfonic acid, alkyl, and acyl can be prepared by first synthesizing one of these substituted benzenes and then chemically changing the substituent. The kinds of substituents that can be placed on benzene rings are greatly expanded by reactions of arene dia-zonium salts, nucleophilic aromatic substitution reactions, and reactions involving a benzyne intermediate. The relative positions of two substituents on a benzene ring are indicated either by numbers or by the prefixes ortho, meta, and para. 

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