Sulfonyl halides conversion

In this connection it should be mentioned that dihalogenomethyl methyl ethers did not furnish the expected jS-disulfone nor the a-halogeno sulfones as preliminary steps in appreciable amounts surprisingly, sulfonyl halides have been isolated as main products of these conversions ... 

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). 

Substitution of fluorine for halogen in aromatic and alkyl sulfonyl halides can be carried out with or without using a solvent. An aqueous system such as 70 % aqueous potassium fluoride is also used because the rate of hydrolysis is much slower than the rate of fluorination as reported for the conversion of methanesulfonyl chloride (1) to methanesulfonyl fluoride (2).23... 

Sulfonic acids are converted to the corresponding acid halides in much the same way as carboxylic acids. Thionyl chloride is the best reagent for the preparation of methanesulfonyl chloride (83%). By heating with a large excess of thionyl chloride, however, p-toluenesulfonic acid is converted into its anhydride (87%). Benzenesulfonyl chloride is made in 80% yield by the action of either phosphorus pentachloride or phosphorus oxychloride at 180° on sodium benzenesulfonate. Chlorosulfonic and fluorosulfonic acids are used in the conversion of sodium p-chloro-benzenesulfonate to the corresponding sulfonyl halides (85 8S>%). ... 

Alkanesulfonyl chlorides, when treated with diazomethane in the presence of a base (usually a tertiary amine), give episulfones (79). " ° The base removes HCl from the sulfonyl halide to produce the highly reactive sulfene (78) (17-14), which then adds CH2. The episulfone can then be heated to give off SO2 (17-20), making the entire process a method for achieving the conversion RCH2SO2CI RCH=CH2. ° ... 

Sulfonic esters are most frequently prepared by treatment of the corresponding sulfonyl halides with alcohols in the presence of a base. This procedure is the most common method for the conversion of alcohols to tosylates, brosylates, and similar sulfonic esters. Both R and R may be alkyl or aryl. The base is often pyridine, which functions as a nucleophilic catalyst, as in the similar alcoholysis of carboxylic acyl halides (16-61). Propylenediamines have also been used to facilitate tosylation of an alcohol. Silver oxide has been used, in conjunction with KI. Primary alcohols react the most rapidly, and it is often possible to sulfonate selectively a primary OH group in a molecule that also contains secondary or tertiary OH groups. The reaction with sulfonamides has been much less frequently used and is limited to A,A-disubstituted sulfonamides that is, R— may not be hydrogen. However, within these limits it is a useful reaction. The nucleophile in this case is actually RO . However, R may be hydrogen (as well as alkyl) if the nucleophile is a phenol, so that the product is RS020Ar. Acidic catalysts are used in this case. Sulfonic acids have been converted directly to sulfonates by treatment with triethyl or trimethyl orthoformate, HC(OR)3, without catalyst or solvent and with a trialkyl phosphite, P(OR)3. ... 

A commonly used and important reaction of sulfonic acids, or sulfonates, is their conversion to sulfonyl chlorides by treatment with phosphorus halides, or sometimes with thionyl chloride. Although it is easy to postulate mechanisms for this conversion, the exact path followed has never been determined. Similarly, although mechanisms can be suggested for other known reactions involving sulfonic acids, such as the cleavage of dialkyl ethers by anhydrous sulfonic acids (Klamann and Weyerstahl, 1965), or the formation of sulfones by treatment of an aromatic hydrocarbon with a mixture of sulfonic acid plus polyphosphoric acid (Graybill, 1967), nothing truly definitive is known about the details of the actual mechanisms of these reactions. 

A variety of procedures have been identified for the interconversion of sulfonyl derivatives. Because of their high acidity, sulfonic acids can readily be neutralized with inorganic bases or organic amines to form salts. Conversion of metal salts back to the acid form is often desirable in synthetic or electroplating applications. Direct acidification of alkali metal sulfonates with HCl affords the sulfonic acid with precipitation of the formed metal halide salt. An alternative approach is to convert the salt back to the acid by elec-trodialysis. Recovery and recycle of MSA from spent metal plating baths have been described. 

Scheme 2.178 Conversion of sulfonyl and sulfinyl halides to the corresponding trifluoromethyl sulfones and sulfoxides by nucleophilic trifluoromethylation [38].

Chlorosulfonic acid is widely used in organic qualitative analysis to prepare solid derivatives from liquid or low melting aromatic compounds, e.g. hydrocarbons, halides and ethers." The procedure involves conversion of the aromatic compound into the sulfonyl chloride, which is subsequently reacted with ammonia to yield the solid sulfonamide derivative which is suitable for melting point determination, Chlorosulfonic acid reacts with carboxylic acid anhydrides to give excellent yields of the acid chlorides (Equation 11). 

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