Sulphenylation

TABLE 13. Synthesis of ally sulphoxides from sulphenyl chlorides, RSC1, and allyl alcohols R Alcohol Sulphoxide Yield (%) Ref. 

TABLE 14. Allenic sulphoxides from propargylic alcohols and sulphenyl chlorides, RSC1... 

Julia and coworkers have utilized the sulphenylation reaction in the synthesis of / , y-unsaturated dithiocarboxylates 494, via the reaction sequence shown in equation 298557. 

Unsymmetrical thiosulphinates and thiosulphonates are both oxidized by potassium superoxide in pyridine in the presence of 18-crown-6 ether to produce sulphinic and sulphonic acids and a disulphide, under mild conditions (equation 84)200,201. Sulphinic and sulphonic acids were produced from both the R and R substituents whilst the disulphide was derived only from the sulphenyl side of the reactant. Thus, the reaction mixture contained five products, making the reaction not synthetically useful. Pyrolysis of thiosulphinates also produces mixtures of products, one being the thiosulphonate again this is not a synthetically useful reaction202. 

Reaction of equimolar amounts of the thiocarbamate (91) with (chlorocarbonyl)sulphenyl chloride gave l,2,4-dithiazoline-5-one (92) and the 1,2,4-thiadiazole (93) the relative amounts of (92) and (93) being very dependent on the solvent used in the reaction. The mechanism of formation of both (92) and (93) was discussed <96JOC6639>. 

Rearrangement of acetylenic sulphenates to the allenic sulphoxides 151 was discovered when the synthesis of propargylic ester of trichloromethanesulphenic acid 152 was attempted (equation 86). This reaction is of general scope and gives very good yields of allenic sulphoxides (Table 14) from structurally diverse cohols and various sulphenyl chlorides Reaction of alkynols 153 with benzenesulphenyl chloride in the presence... 

In contrast to the early theoretical work of Rank and coworkers , C-NMR investigations had revealed that the metallated carbon atom in the a-sulphinyl carbanion is nearly planar . A four-centre chelate structure 315 has been proposed for a-lithiosulphoxides, and it is believed to be responsible for the planar configuration of the anionic carbon atom and for the greater stability of o(-sulphinyl carbanions in comparison with a-sulphenyl carbanions This chelation favours one of the two diastereoisomeric carbanions and for this reason a-sulphinyl carbanions react with electrophiles in a highly stereoselective manner (see below). 

PLE pressurized liquid extraction, SPE solid phase extraction, UE ultrasonic extraction, DSPE dispersive solid phase extraction, SBSE stir bar sorptive extraction, TD-GC-MS thermal desorption-gas chromatography-mass spectrometry, LAS linear alkylbenzene sulfonates, CDEAs coconut diethanol amides, NPEOs nonylphenol ethoxylates, DP degradation products, SPC sulphenyl carboxylates, PCDD dibenzo-p-dioxins (PCDD), PCDF dibenzofurans, PCBs biphenyls... 

Sulphenyl chlorides, e.g. C13CSC1, can also be used as sources of thiyl radicals, but here the addition is initiated by Cl- and the R S will thus become attached to the other carbon atom of the double bond ... 

On reacting 3,3-disubstituted-l,2-alkadienephonic dialkyl esters with methyl-sulphenyl chloride, 1,2-oxaphosphole derivatives and 1,2-adducts were isolated [108], In the case of dialkyl esters of 3-methyl-1,2-butadienephosphonic acid, the formation of dialkyl esters of 1,3-butadienylphosphonic acid was also detected (Scheme 45). 

It has been established that alkadienephosphonates bearing bridge-substituent at C3 atom of the alenephosphonate system on reaction with alkyl(aryl)sulphenyl chlorides lead to the formation of spyrocompounds [111]. 

The 1,2-alkadienephosphine oxides react smoothly with dialkoxyphosphonyl-sulphenyl-chlorides affording 2,5-dihydro-l,2-oxaphosphonium salts 145 and 146 (Scheme 59) [117]. 

Similar to the reaction pathway discussed above, 181 reacts with dialkoxyphos-phonyl-sulphenyl chlorides affording 184 (Scheme 74) [117],... 

The iodo-phosphine (50) decomposes at temperatures above —50 °C to give the phosphorane (51).42 Phosphorus trichloride is oxidized by the sulphenyl chloride (52).48 Aryl- and alkyl-dichlorophosphines have been converted into the phosphor-... 

In a chemical model for oxidative phosphorylation77 the anaerobic oxidation of iV-benzyl 1,4-dihydronicotinamide by a pyridine solution of haemin was accompanied by the synthesis of ATP from ADP and inorganic phosphate. In support of an alternative chemical model involving sulphenyl phosphates as the reactive species,78 lipophilic thioureas have been shown to inhibit mitochondrial oxidative phos-... 

Monodesulphuration of diaryl thioketals and bis-sulphenylated j8-dicar-boxyl compounds, diorganyl trisulphides and disulphides... 

The method employs mild experimental conditions and is therefore competitive with the existing methods for the preparation of benzhydryl sulphides and sulphenylated -dicarbonyl compounds. ... 

If Lewis acid-sensitive double bonds are located in the residues R or R, an indirect oxidation of the vinylic hydrogen via lithiation/sulphenylation turns out to be a good solution and it was applied during the final steps of (-l-)-eldanolide (358) synthesis (equation 97) . ... 

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