Sulfones from alkyl halides

A reaction also known for a long time is the formation of sulfones from alkyl halides and alkali sulfinates,357 which is usually effected in aqueous or alcoholic solution at water-bath temperatures ... 

The Grignard reagents used in the reaction may be either those derived from aryl halides or those formed from alkyl halides. Phenyllithium reacted with the tosylate to give sulfones rather than azoxy compounds. 

Tributyltin hydride, 316 Zinc iodide, 280 From alkyl halides Lithium aluminum hydride-Ceri-um(III) chloride, 159 Palladium catalysts, 230 Sodium cyanoborohydride-Tin(II) chloride, 280 From alkyl sulfonates Lithium triethylborohydride, 153 From thiols... 

SECTION 140 Halides and Sulfonates from Alkyls, Methylenes, and Aryls... 

SECTION 220 Oxides from Alkyl Halides and Sulfonates... 

Sodium sulfhydride (NaSH) is a much better reagent for the formation of thiols (mercaptans) from alkyl halides than H2S and is used much more often. It is easily prepared by bubbling H2S into an alkaline solution, but hydrosulfide on a supported polymer resin has also been used. " The reaction is most useful for primary halides. Secondary substrates give much lower yields, and the reaction fails completely for tertiary halides because elimination predominates. Sulfuric and sulfonic esters can be used instead of halides. Thioethers (RSR) are often side products. The conversion can also be accomplished under neutral conditions by treatment of a primary halide with F and a tin sulfide, such as PhsSnSSnPhs. An indirect method for the preparation of a thiol is the reaction of an alkyl halide with thiourea to give an isothiuronium salt (119), and subsequent treatment with alkali or a... 

Although several methods have been reported, the synthesis of iV-monoalkylhydroxylamines from alkyl halides or sulfonates has remained difficult. Relating to this a new preparation of A -alkylhydroxyl-amines is based upon N-alkylation of isoxazole derivative (52). Besides 2-propyl iodide several primary alkyl halides have been described as the alkyladon agent in this procedure (equation 23). ... 

SECTION 140 HALIDES AND SULFONATES FROM ALKYLS. METHYLENES AND ARYLS... 

One of the most commoidy used methods for forming carbon-carbon double bonds is by -elimination reactions of the types shown in Scheme 2.1, where X = e.g. OH, OCOR, halogen, OSO2R, NRa, etc. Included among these reactions are acid-catalysed dehydrations of alcohols, solvolytic and base-induced eliminations from alkyl halides or sulfonates and the Hofmann elimination from quaternary ammonium salts. They proceed by both E2 (elimination bimolecular) and E1 (elimination... 

Aikyl fluorides by exchange from alkyl halides or methanesulfonates. The resin used for the reaction is the F form of Amberlyst-A26 (Rohm and Haas), a macroreticular anion-exchange resin containing ammonium groups. When this material and primary alkyl halides or sulfonates are refluxed in a solvent (pentane, hexane, ether), alkyl fluorides are formed, usually in satisfactory yields. Alkenes accompany fluorides in the reaction of secondary substrates. This reaction has been conducted previously under phase-transfer catalysis (5, 322). ... 

Sulfonate esters are subject to the same limitations as alkyl halides Competition from elimination needs to be considered when planning a functional group transforma tion that requires an anionic nucleophile because tosylates undergo elimination reactions just as alkyl halides do... 

An advantage that sulfonate esters have over alkyl halides is that their prepara tion from alcohols does not involve any of the bonds to carbon The alcohol oxygen becomes the oxygen that connects the alkyl group to the sulfonyl group Thus the configuration of a sulfonate ester is exactly the same as that of the alcohol from which It was prepared If we wish to study the stereochemistry of nucleophilic substitution m an optically active substrate for example we know that a tosylate ester will have the same configuration and the same optical purity as the alcohol from which it was prepared... 

Sulfonate esters are especially useful substrates in nucleophilic substitution reactions used in synthesis. They have a high level of reactivity, and, unlike alkyl halides, they can be prepared from alcohols by reactions that do not directly involve bonds to the carbon atom imdeigoing substitution. The latter aspect is particularly important in cases in which the stereochemical and structural integrity of the reactant must be maintained. Sulfonate esters are usually prepared by reaction of an alcohol with a sulfonyl halide in the presence of pyridine ... 

TABLE 3. Sulfones from sulfinates R1S02M and alkyl halides... 

Alkylation of carbanions derived from allyl aryl sulfones 236 with alkyl halides is known... 

Formation of Alkyl Halides from Esters of Sulfuric and Sulfonic Acids... 

---