SYNTHESIS aryl sulfonates

Three forms of caustic soda are produced to meet customer needs purified diaphragm caustic (50% Rayon grade), 73% caustic, and anhydrous caustic. Regular 50% caustic from the diaphragm cell process is suitable for most appHcations and accounts for about 85% of the NaOH consumed in the United States. However, it caimot be used in operations such as the manufacture of rayon, the synthesis of alkyl aryl sulfonates, or the production of anhydrous caustic because of the presence of salt, sodium chlorate, and heavy metals. Membrane and mercury cell caustic, on the other hand, is of superior quaUty and... 

Poly(arylene thioether)s, 363-364 Poly(arylene thioether sulfone)s, 364 Poly(aryl sulfone) derivatives, 354 Poly(p-benzamide), synthesis of, 188-189 Polybenzimidazoles (PBIs), 265 ferrocene-containing, 315 synthesis of, 313... 

Chiral exocyclic alkenes such as 112, also having the chiral center two bonds away from the reacting alkene moiety, have been used in highly diastereoselective reactions with azomethine ylides, and have been used as the key reaction for the asymmetric synthesis of (5)-(—)-cucurbitine (Scheme 12.37) (169). The aryl sulfone 113 was used in a 1,3-dipolar cycloaddition reaction with acyclic nitrones. In 113, the chiral center is located four bonds apart from alkene, and as a result, only moderate diastereoselectivities of 36-56% de were obtained in these reactions (170). 

The formation of bonds to aromatic rings is the foundation of much of organic synthesis. There has been much excitement over the past several years around Pd- or Cu-mediated displacement of an aromatic halide or aryl sulfonate with an amine. Paul Knochel of the University of Munich reports (Angew. Chem. Int. Ed. 2004,43, 897) a complementary approach, the addition of an aryl halide-derived Grignard such as 2 to the diazonium derivative 3. Aryl triflates such as 4 are efficient partners for further coupling. 

Climent, M. J., Corma, A., Guil-Lopez, R., Iborra, S. and Primo, J. Solid catalysts for the production of fine chemicals the use of ALPON and hydrotalcite base catalysts for the synthesis of aryl sulfones, Catal. Lett., 1999, 59, 33-38. 

Our strategy for the Smij-promoted synthesis of l,2-cis-C-glycosides is illustrated in Figure 3. It was assumed that one-electron transfer to the LUMO of the aryl sulfone group in A would result in concomitant cleavage of the C1 -S bond liberating an anomeric radical intermediate, as previously observed in the reductive lithiation of glycosyl phenyl sulfones." If 5-exo cyclization onto the silicon-tethered alkene/alkyne is substantially favored over a second electron transfer from Smij, then the exocyclic carbon radical B would ultimately be formed. On the other hand, reduction of the Cl-radical by... 

Aryl sulfones have been prepared from sulfinic acid salts, aryl iodides and Formation of thiocyanates from unactivated aryl halides has been accomplished with charcoal supported copper(l) thiocyanate. " The copper catalyzed reaction of Na02SMe and aryl iodides give the aryl methyl sulfone. " A similar synthesis of diaryl sulfones has been reported using a palladium catalyst. " ... 

Hu Y, Chen ZC, Le ZG et al (2004) Organic reactions in ionic hquids a new method for the synthesis of alkyl aryl sulfones by alkylation of sodium aienesulfinates with unactivated alkyl... 

Without the reducing agent (e.g., H2) aryl sulfonates are converted into esters in ROH under basic conditions (a protocol indicates addition of the hydrofluoroborate salt of 1,3-biscyclohexylphosphinopropane). In an analogous synthesis of amides in DMSO, in which amines replace ROH, the PhONa base appears to play a special and critical role. With Al(OTf)3 cocatalyst 1-alkenes are transformed into saturated esters favoring the hnear isomer (against the branched isomer in a ratio of >2 1). ... 

Synthesis of carotinoids via sulfones. FischU and Mayer have developed a synthesis of carotinoids based on the fact that allylic aryl sulfones in the presence of base readily eliminate arylsulfinic acid with formation of a conjugated double bond. An example is the synthesis of 15,15 -dehydro- 3-carotene... 

Haller-Bauer reaction, 525 a-Halo acyl chlorides, 75 2-Haloethyl esters, 553 y-Halo ketones, 524 Halomcthyl aryl ketones, 103 Halomethyl aryl sulfones, 41 Halomethylation, 105 tj-Halo-l-phenyl-l-alkynes, 165 Halopropyl isocyanates, 570 2-Halopyridines, 479 Halo-a,p-unsaturated ketones, 647-648 p-Halovinyl ketones, 644 Haworth succinic anhydride synthesis, 474 Hemithioacetal interchange, 381-382... 

This reaction has been further extended to a catalytic procedure for the synthesis of allyl aryl sulfone derivativesl47 from Baylis-Hillman acetates 145 and sulfonyl hydrazides 146 using BU4NI as the catalyst and TBHP as an oxidation agent in water (Scheme 4.74) [116],... 

Introduction of arylsulfonylmethyl substituents into nitroheteroaromatic rings is of great practical value because these sulfones are versatile intermediates in organic synthesis. Nitrobenzyl aryl sulfones and their heterocyclic analogues can easily be transformed into the corresponding ethenyl derivatives by a simple alkylation with simultaneous elimination of arylsulfinate anion [125]. Diethyl methylenemalonate substituent can be introduced in the positimi 4- of 5-nitroimidazole via the VNS reaction of 5-nitroimidazole with the carbanion of chloromethyl phenyl sulfone [112, 124], followed by condensation of the obtained 4-(phenylsulfonyl)methyl derivative with diethyl bromomalonate or diethyl ketomalonate (Scheme 33) [126]. 

Apart from aryl halides, other very easily available substrates for nickel-catalysed biaryl (II) synthesis are aryl sulfonates (XII). Method D is very efficient in the homocoupling reactions of substituted aryl sulfonates in good to excellent yields [15], Table 6. Substituted aryl sulfonates are readily obtained from phenols and trifluoromethanesulfonic anhydride, benzenesulfonyl-, tosyl- or methanesulfonyl chloride in pyridine, or in a suitable inert solvent such as dichloromethane in the presence of triethylamine or Hiinig s base. Among other nickel complexes, Ni(dppe)Cl2 and Ni(dppf)Cl2 have been used (10 mo1%) as slightly less versatile catalysts for the homo-couplings of naphthyl sulfonates in refluxing THF, DMF or their mixtures [42]. 

Vinyl and aryl sulfonates Preparations and applications in total synthesis 12COS806. 

The synthesis of trisubstituted alkenes has scarcely been disclosed some exanples may be found in the work of Najera and coworkers using electron-deficient aryl sulfones 47 combined with phosphazene tScheme 19.21T The scope is even more limited for tetrasubstituted olefins as the yields are quite low. Acylsilanes afford trisubstituted vinylsilanes such as 48 mainly as the E isomers, but the stereoselectivity can be controlled by modulating the nature of the silyl group tScheme 19.22T E-configured conjugated esters and Weinreb amides have been synthesized successfully as well by Najera and coworkers starting from conveniently substituted arylsulfone 49 (Scheme 19.23). 

The oxidation of primary alkyl aryl sulfones by O2 in THF resulted in formation of the corresponding carboxylic acids in fair to excellent yield in the presence of a base used for double deprotonation of the sulfones. The method was used for the convenient synthesis of C-labelled carboxylic acids. ... 

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