Trimethylsulfonium bromide

Reaction of cyclobutanones with trimethylsulfonium bromide in the presence of a base gave epoxides.65,332 The opposite configuration with respect to the epoxide is achieved65 when using this strategy vs. the epoxidation of the corresponding methylenecyclobutane with a peracid (see Section 5.1.2.2.). 

Framen s procedure. A solution of potassium /-butoxide in DMSO is added by drops to a solution of trimethylsulfonium bromide or perchlorate in DMSO at room temperature. Sodium methoxide and sodium ethoxldc serve also as the base, and DMF is satisfactory as solvent. Reagent generated by this method converts mono-functional aldehydes and ketones into epoxides in good yield. I ranzcn initially... 

The decomposition of the ylid in the presence of phenylsodium should be contrasted to the decomposition of the ylid with dimethoxyethane 169) where only polymethylene is observed (74%). It is worth noting that when dimethylsulfoniummethylide is decomposed in dimethylsulfoxide, ethylene is produced 34> however, when this ylid is generated in ether by treatment of trimethylsulfonium bromide with phenyllithium, polymethylene is formed in 70% yield 168h It has also been shown that if lithium iodide is treated with diazomethane in ether, both polymethylene (12%) and ethylene (67%) are formed 180>. However, only a trace (0.4%) of norcarane is noted, when this decomposition is carried out in the presence of cyclohexene 180>. 

Trifluoromethanesulfonic acid, Acyl chlorides, Aromatic hydrocarbons, 0375 Trimethylsulfonium chloride, 1303 Trimethylsulfoxonium bromide, 1299 Uronium nitrate, 0494... 

A rather more complex scheme is required for the preparation of a derivative that bears a trifluoromethyl substituent on one of the benzene rings. The scheme starts with the condensation of the nitrile group in (32-1) with phenyhnagnesium bromide to give the corresponding imine treatment with aqueous acid leads to the substituted benzophenone (32-2). The future methyl on one of the bridges is introduced in a sequence involving the addition of a trimethylsulfonium yhde. 

Trimethylsilylprop-2-enyl trifluoromethanesulfonate, 2843 3-Trimethylsilyl-2-propyn-1 -ol, 2489b iV-Trimethylsilyl-iV-trimethylsilyloxyacetoacetamide, 3369 Trimethylstibine, see Trimethylantimony, 1316 Trimethylsulfonium chloride, 1299 Trimethylsulfoxonium bromide, 1295 Trimethylthallium, 1317 f 2,4,6-Trimethyltrioxane, 2509 Trinitroacetonitrile, 1005... 

Trifluoromethyl hypofluorite, Lithium, 0352 2,4,6-Trimethylpyrilium perchlorate, 2987 Trimethylsulfonium chloride, 1299 Trimethylsulfoxonium bromide, 1295 Urea hydrogen peroxidate, 0475... 

Ligand coupling takes place in the course of the evolution of the products of the reaction of triphenylcyclopropenium bromide (6) with trimethylsulfonium methylide (7)7 (Scheme 3.2)... 

In the case where liquid chromatography is not available, acidic herbicides need to be derivatized because they can dissociate in water and are not usually volatile to be analyzed by gas chromatography. The basic methods used for chlorophenoxy acid herbicides are esterification, silylation, and alkylation, as described in a recent exhaustive review.The derivatization step is performed after preconcentration and cleanup. The step consists of the formation of esters and ethers from the carboxyl and phenol groups of the acidic herbicides. A lot of reagents and chemical mechanisms can be used to perform derivatization reactions. The most employed derivatization reagents are diazomethane, methyliodide, trimethylsulfonium (or anilinium) hydroxide, bis (trimethylsilyl) trifluoroacetamide (BSTFA), pentafluorobenzyl bromide, and anhydride acetate. It should be noted that explosive and hazardous diazomethane was replaced by safer agents. Authors also underline that surface water generally contains humic substances, which can interfere with the derivatization reaction. ... 

The salt is prepared by quaternization of (-)-ephedrine with methyl bromide. Asymmetric oximne synthesis. Japanese chemists have reported asymmetric synthesis of 2-phenyloxirane from benzaldehyde and dimethylsulfonium methylide generated from trimethylsulfonium iodide in 50% NaOH with the chiral phase-transfer catalyst (-)-N,N-dimethylephedrinium bromide (1). 

Sulfur ( S)(I= 3j2). S NMR chemical shifts were calculated by the scaled DFT and EMPI approaches for the fluoride, chloride and bromide of trimethylsulfonium ion and S-methyltetrahydrothiophenium ion, in addition to the free cations. and S NMR chemical shifts of sulfur dioxide (SO2) were measured for the range of density (0.05-0.3 mol L ) in the gas phase at 300 and 333 K The chemical shifts for both nuclei are linearly dependent on density showing an increase of magnetic shielding and a decrease of S shielding due to intermolecular interactions. ... 

The reaction of trimethylsulfonium iodide with benzaldehyde under basic phase transfer conditions catalyzed by chiral quaternary ammonium salts such as (-)-N,N-dimethyl-ephedrinium bromide has been reported to yield styrene oxide in high optical purity [19], which may be somewhat overestimated [20]. 

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