Aryl sulfinyl chlorides

The catalytic activation of thionyl chloride by Bi(0Tf)3-xH20 has been reported and applied to the preparation of the thermally unstable aryl sulfinyl chlorides [34]. It has been shown that this procedure is restricted to electron-rich aromatics (such as aromatic ethers and mesitylene). The mechanistic investigation seems to indicate that no ligand exchange occurs during the reaction. 

Aryl sulfinyl azides, ArS(0)N3, can be prepared at low temperature by reaction of sulfinyl chloride ArS(0)Cl with sodium azide (Maricich and Hoffman, 1974). On warming to 0° they decompose with evolution of nitrogen, their decomposition exhibiting clean first-order kinetics ( = 3 x 10-4 s-1 for PhS(0)N3 in acetonitrile at 0°). The rate-determining step of the decomposition is loss of nitrogen from the sulfinyl azide to form the sulfinyl nitrene ArS(0)N (143). The subsequent behavior of this nitrene suggests (Maricich and... 

Recently, sulfinyl and sulfonyl peroxy radical intermediates 6a and 6b have been prepared by the reactions of aryl sulfinyl or sulfonyl chloride with superoxide anion radical, respectively. These peroxy intermediates show strong oxidizing abilities in various oxidations. This chapter will describe the properties and applications of a variety of sulfur and phosphorus peroxy compounds in oxidation reactions. For a more complete picture, readers should consult the original papers cited in the areas that most interest them. 

A concerted elimination-cyclization mechansim, involving a sulfenyl halide in a 1,3-butadiene-1-thio system, is the most probable mechanism for the formation of benzo[6 Jthiophenes from cinnamic acids or 4-aryl-2-butanones by treatment with thionyl chloride. The reactions shown in Scheme 5 have been carefully worked out, and the intermediates isolated (75JOC3037). The unique aspect of this synthesis is the reduction of the sulfinyl chloride (a) by thionyl chloride to form the sulfenyl chloride (b). The intermediate (b) was isolated and converted in pyridine to the 3-chlorobenzo[6]thiophene-2-carbonyl chloride in 36% yield (73TL125). The reaction is probably initiated by a sulfenyl ion attack on the aromatic ring, since it is promoted by electron-releasing groups para to the site of ring closure. For example, when X in (36) was N02, a 23% yield of (37), a mixture of 5-and 7-nitro derivatives, was obtained, but when X in (36) was OMe, a 54% yield of (37) was obtained, contaminated with some 3,4-dichloro-5-methoxybenzo[6]thiophene-2-carboxylic acid. 

S-Aryl thiosulfonates. This novel preparation involves reaction of arene-sulfinyl chlorides with the reagent in pyridine. The products are powerful sulfenylat-ing agents. 

Kresze G, Wucherpfennig W. Reactions with N-sulfinyl-compounds. 8. Formation and fragmentation of N-aryl-sulfonyl-imide chlorides. Chem. Ber. Rec. 1968 101(1) 365-370. 

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