Sodium arenesulfinates

Arenesulfinate esters are usually prepared from an arenesulfinyl chloride and an alcohol in ether and pyridine. The arenesulfinyl chloride is usually prepared from the sodium arenesulfinate which is made by reduction of the arenesulfonyl chloride, preferably by aqueous sodium sulfite. After the crystalline sulfinate epimer has been removed by filtration, the equilibrium between the epimers remaining in the mother liquor may be reestablished by the addition of hydrogen chloride as shown by Herbrandson and Cusano . In this way the yield of the least soluble diastereomer may be increased beyond that which exists in the original reaction mixture (Scheme 1). Solladie prepared sulfinate ester 19 in 90% yield using this technique and published the details of his procedure. Estep and Tavares also published a convenient recipe for this method, although their yields were somewhat lower than Solladie s. 

Palladium-catalyzed cross-coupling reactions of diaryliodonium tetrafluo-roborates have recently been employed for conversions of mercaptans to aryl-and diaryl sulfides, sodium arenesulfinates to diaryl sulfones, and dialkyl phosphites to aryl phosphonates (Scheme 43) [120-122]. 

Allylic sulfones. The reaction of 1,3-dienes with arenesulfinic adds or sodium arenesulfinates in THF in the presence of this palladium catalyst and tri-phenylphosphine results in allylic sulfones. The more substituted isomer is formed predominately ... 

Sulfonyl radicals. Generated from sodium arenesulfinates, the radicals react with alkenes. 

Coupling reactions of alkenyl halides with alkynes and allene are valuable for assembling enynes and 2-sulfonylmethyl-l,3-dienes, with sodium arenesulfinates present in the latter cases. 

Several examples of S-arylation of sulfides and P-arylation of phosphines using diaryliodonium salts were reported in the older literature [877,878]. These reactions generally proceed by a radical chain mechanism. The arylation of phosphines has been used to promote the photo-initiation of cationic polymerization [879]. More recently, the synthesis of diaryl sulfones via S-arylation of sodium arenesulfinates, ArS02Na, by diaryliodonium salts has been reported [880]. 

Sodium arenesulfinates form aryl alkyl sulfones in PT-catalyzed reactions with alkylating agents (eqs. 141 and 142). 

Hu Y, Chen ZC, Le ZG, Zheng QG. Organic reactions in ionic hquids a new method for the synthesis of alkyl aryl sulfones by alkylation of sodium arenesulfinates with unactivated alkyl chlorides. Synth. Commun. 2004 34(21) 4031-4035. 

Complexes such as (6) have been postulated as intermediates in the PdCl2-catalyzed dimerization of arenesulfinic acids or their sodium salts to give the corresponding organic biaryls.36... 

The reaction of benzyl methyl carbonate with sodium benzenesulflnate and different palladium catalysts has shown that the best yields were obtained when a Pd( 3-C3H5)Cl2 - (DPEphos) catalyst was used in DMSO at 80 °C.121 Most of the reactions gave >90% yields of the benzyl aryl sulfone. In the suggested mechanism, the methyl carbonate leaving group is displaced by the catalyst, forming an (j 3-benzyl)palladium intermediate that reacts with the sodium salt of the arenesulfinate. 

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