Alkyl sulfonates coupling

Sulfonic acids are prone to reduction with iodine [7553-56-2] in the presence of triphenylphosphine [603-35-0] to produce the corresponding iodides. This type of reduction is also facile with alkyl sulfonates (16). Aromatic sulfonic acids may also be reduced electrochemicaHy to give the parent arene. However, sulfonic acids, when reduced with iodine and phosphoms [7723-14-0] produce thiols (qv). Amination of sulfonates has also been reported, in which the carbon—sulfur bond is cleaved (17). Ortho-Hthiation of sulfonic acid lithium salts has proven to be a useful technique for organic syntheses, but has Httie commercial importance. Optically active sulfonates have been used in asymmetric syntheses to selectively O-alkylate alcohols and phenols, typically on a laboratory scale. Aromatic sulfonates are cleaved, ie, desulfonated, by uv radiation to give the parent aromatic compound and a coupling product of the aromatic compound, as shown, where Ar represents an aryl group (18). 

Coupling of sulfones to alkenes. In the presence of a catalytic amount of Ni(acac), a-anions of allylic sulfones undergo coupling at the a-position with desulfonylation to give 1,3,5-trienes in good yield. The original double bonds of the sulfone retain their configuration, but both isomers of the newly formed double bond are obtained. The reaction is particularly useful for preparation of C20- and C30-polyisoprenoids. Benzyl and w-alkyl sulfones can also be coupled to form symmetrical alkenes in this way.1... 

In contrast, copper (II) triflatc effects oxidative dimerization of a-anions of n-alkyl sulfones to a-disulfones (meso- and dl- isomers). Coupling of a-anions of allylic sulfones with this catalyst occurs mainly at the /-position.2... 

Alkyl-substituted ruthenocenes, preparation, 6, 635-636 Alkyl sulfonates, cross coupling, and Grignard reactions, 9, 44 Alkyltantalum imido complexes, as catalysts, 5, 193 Alkyl tellurides... 

Alkynes. These reagents undergo clean coupling with tertiary alkyl halides or secondary alkyl sulfonates. ... 

Procedure for the coupling of the alkyl sulfone and the aldehyde to generate the a-alkoxy sulfone. 

Scheme 4-237. Example for the iron-catalyzed cross-coupling of alkyl sulfonates with aryl zinc reagents.

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

The azo coupling reaction proceeds by the electrophilic aromatic substitution mechanism. In the case of 4-chlorobenzenediazonium compound with l-naphthol-4-sulfonic acid [84-87-7] the reaction is not base-catalyzed, but that with l-naphthol-3-sulfonic acid and 2-naphthol-8-sulfonic acid [92-40-0] is moderately and strongly base-catalyzed, respectively. The different rates of reaction agree with kinetic studies of hydrogen isotope effects in coupling components. The magnitude of the isotope effect increases with increased steric hindrance at the coupler reaction site. The addition of bases, even if pH is not changed, can affect the reaction rate. In polar aprotic media, reaction rate is different with alkyl-ammonium ions. Cationic, anionic, and nonionic surfactants can also influence the reaction rate (27). 

Coupling of alkyl halides with Na, supplanted by the coupling ol alkyl halides or sulfonates with Gngnard reagents or RLi in the presence of CufI) salts... 

The oxidative dimerization of the anion of methyl phenyl sulfone (from a Grignard reagent) in ethereal solution in the presence of cupric chloride in 5% yield has been reported47. Despite the reported48 poor stability of the a-sulfonyl C-centered radicals, Julia and coworkers49 provoked the dimerization (in 13 to 56% yields) of the lithiated carbanion of alkyl phenyl sulfones using cupric salts as oxidants. The best results are obtained with cupric triflates in THF-isobutyronitrile medium (56% yield for R = H). For allyl phenyl sulfones the coupling in the 3-3 mode is predominant. 

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