Halides sulfonic acid esters

General Reaction Chemistry of Sulfonic Acids. Sulfonic acids may be used to produce sulfonic acid esters, which are derived from epoxides, olefins, alkynes, allenes, and ketenes, as shown in Figure 1 (10). Sulfonic acids may be converted to sulfonamides via reaction with an amine in the presence of phosphorus oxychloride [10025-87-3], POCl3 (11). Because sulfonic acids are generally not converted direcdy to sulfonamides, the reaction most likely involves a sulfonyl chloride intermediate. Phosphorus pentachloride [10026-13-8] and phosphorus pentabromide [7789-69-7] can be used to convert sulfonic acids to the corresponding sulfonyl halides (12,13). The conversion may also be accomplished by continuous electrolysis of thiols or disulfides in the presence of aqueous HQ [7647-01-0] (14) or by direct sulfonation with chlorosulfuric acid. Sulfonyl fluorides are typically prepared by direct sulfonation with fluorosulfuric acid [7789-21-1], or by reaction of the sulfonic acid or sulfonate with fluorosulfuric acid. Halogenation of sulfonic acids, which avoids production of a sulfonyl halide, can be achieved under oxidative halogenation conditions (15). 

General Reaction Chemistry of Sulfonic Acids. Sulfonic acids may he used to produce sulfonic acid esters, which are derived from epoxides, olefins, alkynes, allenes, and kelenes, as shown in Figure 1. Phosphorus pentachloride and phosphorus pentabromide can be used to convert sulfonic acids to the corresponding sulfonyl halides. 

The alkylation of amides by alkyl halides or simple sulfonic acid esters is usually of little importance because the alkylation equilibrium is placed on the side of the starting compounds. This is not the case, however, in either the alkylation of vinylogous amides (which has been achieved even with alkyl iodides ) or if intramolecular alkylation is possible, e.g. in -(2-haloethyl)amides. In the latter case cyclic iminium compounds (81 equation 51) are readily available by replacing the more nucleophilic halide by less nucleophilic complex anions, which can be achieved by addition of Lewis acids or AgBF4. °-2 ... 

Besides ordinary halides and sulfonic acid esters, the development of transition metal catalyzed processes has enabled allylic alcohols, acetates, carbonates, vinyl epoxides and vinyllactones also to be successfully employed as allylic substrates. 

Sulfonic acids, esters, amides and halides as synthons... 

For the conversion of sulfonic acid esters to halides see section 145 (Halides and Sulfonates from Halides and Sulfonates)... 

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