Sulphinic and Seleninic Acids

In a modified standard route, arenesulphonyl chlorides are easily reduced to sulphinic acids, using a saturated hydrocarbon and AICI3.  

Uchino, K. Suzuki, and M. Sekiya, Chem. Pharm. Bull., 1978, 26, 1837. 

Fields, G. Holt, M. O. A. Orabi, and B. Naseeri-Noori,7. Chem. Soc., Perkin Trans. 1, 1979, 233. 

CHMel/ thus supporting the interpretation of rearrangements of alkenes in liquid SO 2 that is based on the instability of allyl sulphinic acids. Sodium salts of sulphinic acids take the role of co-catalyst in PdClj-catalysed dimerization of butadiene in an alcohol solvent, leading to octa-2,7-dienyl alkyl ethers, and act as arylating agents towards cyclo-octa-1,5-diene in the presence of PdClj.  

Oxidation of sulphinic acids by air (under u.v. irradiation) gives sulphonic acids,but N2O4 leads to unstable sulphonyl nitrites RSO2NO rather than to oxidized products.  

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