Sulfinate salt

The Hquid is basically a methacrylate monomer having a suitable inhibitor to ensure adequate shelf life. A/Ai -Dimethyl-/)-toluidine [99-97-8] is probably the most common polymerization accelerator although A/A/-bis(2-hydroxyethyl)- -toluidine and/or a sulfinate salt, eg, sodium -toluene sulfinate [873-55-2], also maybe used. 

When crude aulfonyl chlorides were used as starting materials, the reaction mixture was washed with a suitable solvent to remove organic impurities. In the case of higher-melting crystalline sulfonyl chlorides, heating to 50 may be necessary to complete their reduction. The solution of the sulfinate salt may be kept overnight, if desired, with no decrease in the yield of sulfonyl cyanide. 

Allylic nitro derivadves undergo iheS l reacdon in aqueous acedc acid. Ailylic sulfones in the presence of a sulfinate salt fEq. 7.21 or allylic lactones If the substrate contains a sidtably located ester group are formed in these reacdons fEq. 7.22. ... 

Sulfin, n, sulfonium, sulfine, HaS. -farbe, /, -farbstoff, m. sulfur dye. -salz, n, sulfonium salt, sulfine salt. -sSure, /. sulfinic acid,... 

Recently, the scope of the allylic substitution has been extended to sulfinate salts 84 to obtain allylic sulfones 85. Due to solubility problems of both nucleophile 84 and carbonate leaving group, a polar solvent mixture of DMF and 2-methoxyethanol had to be employed, which limits the reaction to the use of a phosphine ligand. Thus, various aryl sulfinates 84 and functionalized carbonates 81 could be converted to the corresponding allylic sulfones 85 with good to excellent yields and regioselectivites and complete retention of stereochemistry (eq. 2 in Scheme 20) [65]. 

Oxidation of sulfides and sulfoxides, as discussed above, and alkylation of sulfinate salts are the most common methods used to obtain sulfones for synthetic purposes [71, 109-113], A hydrogen peroxide-urea-phthalic anhydride system was recently proposed as a mild convenient reagent for the efficient preparation of sulfones from organic sulfides [114]. 

Simple ct-fluorosulfides are reduced to the fluoroalkanes by sodium-ethanol [93] (equation 75). Clean conversion of bis(trifluoromethyl) disulfide to trifluoromethyl mercaptan is accomplished with hydrogen sulfide and ultraviolet irradiation [94] (equation 76). Perfluoroalkanesulfonyl fluorides are converted to the sulfinate salts by hydrazine [95] (equation 77)... 

Hydrogenolysis of vinyl sulfones.2 Vinyl sulfones are reduced by Na2S204 and NaHC03 in aqueous ethanol with retention of configuration. The reaction is facilitated by use of a phase-transfer catalyst such as Adogen. The reduction involves addition of HSOz to form a sulfone sulfinate salt which can be trapped by CH3I. The overall reaction thus involves a (3-syn-addition followed by an anti-elimination. This hydrolysis was used in a synthesis of several insect pheromones, such as (Z)-8-dodecenyl-l-acetate (1). 

For concentrations of sulfinate salts greater than about 10"2 M... 

Sulfur nucleophiles have not been widely used in ir-allylpalladium chemistry, principally due to their ability to interfere with the catalyst by coordination. This is a less serious concern for sulfinic acid and sulfinate salts than with sulfides, and as a result, several reports have appeared using RSO2H and RSO2-.211-219 Alkenes allylically functionalized with a leaving group, dienes214 and vinyl nitro con-pounds218 219 have all served as precursors for the required ir-allyl species in these reactions (equations 60 and 61). 

VINYL SUBSTITUTION WITH ORGANIC HALIDES, DIAZONIUM SALTS, ACID CHLORIDES, SULFINATE SALTS AND TRIFLATES... 

Resin-bound 7-keto sulfones, prepared in a straightforward, three-step process comprising alkylation of a resin-bound sulfinate salt, alkylation of a sulfone-supported anion with an epoxide, and Jones oxidation of the 7-hydroxy sulfone, provided a source of structurally diverse three-carbon fragments <2004JC0928>. Reaction with a phenylenediamine to give the 1,5-benzodiazepine presumably occurs via initial imine formation followed by expulsion of the resin-bound sulfone, which acts as a traceless linker (Scheme 73). Yields for this process are a modest 10-38%. 

The alkoxide intermediate 4.61 or 4.62 formed in this case is unstable and forms first the adduct 4.63 or 4.65 and then the sulfinate salt 4.64 or 4.66. The sulfinate salt 4.64 or 4.66 spontaneously eliminates sulfur dioxide and lithium benzothiazole to give the corresponding alkene (Scheme 4.38). 

Alkyl arylsufonates and diaryl sulfones are cleaved by alkali metal amalgams to the corresponding sulfinate salts. Some sterically hindered arylsulfonates, however, undergo cleavage at the ring-S bond [128]. 

Sulfones may also be obtained by alkylation of sulfinate salts (79). The sulfinate anion is an ambidentate nucleophile consequently, alkylation can occur either on sulfur to give the sulfone (74) or oxygen to yield the sulfinate ester (80) (Scheme 31). The reactions of (79) with alkyl iodides in polyethylene glycols as solvents generally afford good yields of the sulfones (74). 

The selenosulfonates (26) comprise another class of selenenyl pseudohalides. They are stable, crystalline compounds available from the reaction of selenenyl halides with sulfinate salts (Scheme 10) or more conveniently from the oxidation of either sulfonohydrazides (ArS02NHNH2) or sulfinic acids (ArS02H) with benzeneseleninic acid (27) (equations 21 and 2 2). Selenosulfonates add to alkenes via an electrophilic mechanism catalyzed by boron trifluoride etherate, or via a radical mechanism initiated thermally or photolytically. The two reaction modes produce complementary regioselectivity, but only the electrophilic processes are stereospecific (anti). Similar radical additions to acetylenes and allenes have been reported, with the regio- and stereochemistry as shown in Scheme 11. When these selenosulfonation reactions are used in conjunction with subsequent selenoxide eliminations or [2,3] sigmatropic rearrangements, they provide access to a variety of unsaturated sulfone products. 

In contrast to the behavior of sulfinate salts toward alkynyliodonium salts, phenylsulfinic acid, 92, in methanol, trap [72] the initially formed ylide, resulting in high yields of (2)-p-sulfonylvinyliodonium salts, 93, [Eq. (48)]. 

An alternative chemoselective monohalogenation of -keto sulfones using potassium halide and hydrogen peroxide could be employed to afford the desired halomethyl sulfone reagents. Furthermore, direct alkylation of sulfinate salts with methylene bromide afforded cr-bromosutfones in moderate yields. ... 

To a stirred solution of Cu(OAc)2 (10 mol%) in iraiic liquid ([bniim]OTf 1 mL) and arylboro-nic acid (1 1 mmol), sodium sulfinate salt (2 1 mmol) was added and stirring was continued at room temperature for 12 h. After completiOTi of the reaction, as monitored by TLC, the crude product was extracted with Et20 (3 x 10 mL). The combined Et20 extracts were concentrated in vacuo and the resulting product was purified by colunm chromatography on silica gel using EtOAc-n-hexane (2 8) as eluent to afford the pure product of aryl sulfone 3 (68-82% yield). The ionic liquid containing Cu(OAc)2 was dried under vacuum and preserved for the next run. All the compounds were characterized from comparison of their physical and spectral properties with those reported for authentic samples in literature. 

In addition to well-known nucleophilic behavior of thiolate anions, sulfmates are also active in substitution reactions. To this end, the conversion of a primary alkyl iodide into an alkyl sulfone has been accomplished by simply stirring the sodium sulfinate salt with the alkyl halide in DMF at room temperature (Scheme 5.20) [21]. While only a few examples were described, this work demonstrates the ability of sulfinate salts to participate in nucleophilic substitution reactions. 

A reasonable entry point to the chemistry would be to convert the carboxylic acids into sulfinate salts [12]. Alternatively, a silver-catalyzed decarboxylative thiolation will generate sulfone precursors [16]... 

For a long time, the organic chemistry of sulfur dioxide was limited to the formation of sulfinate salts and the sulfones derived therefrom. As shown, the sulfones are highly valuable synthetic intermediates for the construction of carbon-carbon single and double bonds, and very often with high stereoselectivity. More recently, the H-ene and hetero-Diels-Alder reactions of sulfur dioxide have been realized under conditions that avoid polymerization of alkenes, dienes, and other unsaturated compounds. Thus, alk-2-ene-1-sulfonyl chlorides are obtained readily from alkenes... 

Thermolysis and/or photolysis of tosylhydrazone salts, accessible by condensation of p-toluene-sulfonyl-hydrazine with aldehydes or ketone, gives rise to elimination of the sulfinate salts and forms the intermediate diazo compound (Scheme 18). Generation of free carbenes by this method is sometimes in doubt and, as a consequence, this method is not included in this chapter except when generation of a carbene from the diazirine or diazo compound is not available. 

---