Bis(dimethylamino)trifluoromethylsulfonium Salze: [CF3S(NMe2)2]+[Me3SiF2]‐, [CF3S(NMe2)2]+[HF2]‐ und [CF3S(NMe2)2]+[CF3S]‐

Bis(dimethylamino)trifluoro sulfonium Salts: [CF₃S(NMe₂)₂]⁺[Me₃SiF₂]^‐, [CF₃S(NMe₂)₂]⁺ [HF₂]^‐ and [CF₃S(NMe₂)₂]⁺[CF₃S]^‐ From the reaction of CF₃SF₃ with an excess of Me₂NSiMe₃ [CF₃(NMe₂)₂]⁺[Me₃SiF₂]^‐ (CF₃‐BAS‐fluoride) ( 5 ), from CF₃SF₃/CF₃SSCF₃ and Me₂NSiMe₃ [CF₃S(NMe₂)₂]⁺‐ [CF₃S]^‐ ( 7 ) are isolated. Thermal decomposition of 5 gives [CF₃S(NMe₂)₂]⁺ [HF₂]^‐ ( 6 ). Reaction pathways are discussed, the structures of 5 ‐ 7 are reported.     

Synthesis of 2-substituted 4,5-dihydro-4-oxo-3-furancarboxylates using acylative intramolecular cyclization of sulfonium salts

A simple and efficient synthesis of 4,5-dihydro-4-oxo-3-furancarboxylates using an acylative intramolecular cyclization of sulfonium salts is described. The reaction involved the efficient formation of a mixed anhydride between a linear carboxylic acid and trifluoroacetic anhydride in the presence of N-methylimidazole, followed by the sequential conversion into a highly reactive acylammonium species in situ. This procedure is easily handled, uses readily available inexpensive reagents, and provides a variety of 2-substituted 4,5-dihydro-4-oxo-3-furancarboxylates.     

SYNTHESIS OF SPIRO [1,3-BENZODIOXOLE-2,4′-(3′H) QUINAZOLINES]

Abstract

In the present investigation, the authors could obtain a new series of spiranes (1) through the reaction of the high potential quinone tetrachloro-o-benzoquinone with 2-aryl-3-phenyl-3H-quinazoline-4-thiones. Thus, 2,3-diphenyl- (2a), 2-p-tolyl-3-phenyl- (2b) and 2-p-anisyl-3-phenyl- (2c)-3H-quinazoline-4-thiones react readily with tetrachloro-o-benzoquinone, in boiling toluene, to give the corresponding spiro-1,3-benzodioxole-2,4′-(3′H)-quinazolines (1a-c), respectively.     

An efficient synthesis of isothiazolidines via sulfonium ylides formed by the reaction of thietanes and nitrene

An efficient synthesis of isothiazolidines in good yields is described.     

Synthesis of β‐Hydroxy α‐Sulfanyl Esters by Using Nanocrystalline Magnesium Oxide

Aldol‐type reaction between electron deficient aldehydes and sulfonium salts to afford the corresponding β‐hydroxy α‐sulfanyl esters in moderate‐to‐good yields by using nanocrystalline MgO is described. The sulfanyl group is a useful group for further transformations in organic synthesis. Low R_f‐value isomer is anti‐configured as revealed by X‐ray diffraction study and consistent with the assignment of ¹H‐NMR spectrum.     

Sulfonium Salts as Acceptors in Electron Donor-Acceptor Complexes

The photoactivation of electron donor-acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation of radical species. Electron donor-acceptor (EDA) complexation, however, imposes electronic constraints on the donor and acceptor components and this can limit the range of radicals that can be generated using the approach. New EDA complexation strategies exploiting sulfonium salts allow radicals to be generated from native functionality. For example, aryl sulfonium salts, formed by the activation of arenes, can serve as the acceptor components in EDA complexes due to their electron-deficient nature. This “sulfonium tag” approach relaxes the electronic constraints on the parent substrate and dramatically expands the range of radicals that can be generated using EDA complexation. In this review, these new applications of sulfonium salts will be introduced and the areas of chemical space rendered accessible through this innovation will be highlighted.     

Studies on DMSO-containing carbanilation mixtures: chemistry,oxidations and cellulose integrity

The oxidative effect of carbanilation mixtures containing dimethylsulfoxide (DMSO) was demonstrated by means of alcohol model substances in which competitive carbanilation was prevented due to steric hindrance of the hydroxyl function, rendering those compounds specific probes for oxidation effects. Dimethylsulfonium ions and derived ylide species were shown to be the actually oxidizing species according to trapping methodology using lipophilic olefins which were converted into the corresponding cyclopropane and epoxide derivatives. The experimental data were in good agreement with DFT computations carried out on the B3LYP/6-311+G(d,p) level of theory. The direct interaction of cellulose and sulfoxide solvent was proven by means of methyl-(2-naphthyl)sulfoxide (MNSO) as a model for DMSO, which caused introduction of UV-detectable methylthionaphthyl ether moieties into the cellulose, formed in Pummerer-type side reaction paralleling the chemical behavior of DMSO. A facile color test—responding to sulfoxide-derived oxidizing species—was developed to assess the suitability of carbanilation conditions with regard to cellulose oxidation and degradation. DMSO-based carbanilation systems have to be used with great caution for determination of molecular weight parameters and for similar purposes which require complete maintenance of the cellulose integrity. Cellulose oxidation/degradation by DMSO-derived intermediates upon carbanilation can be minimized but cannot be avoided completely. Thus, if cellulose integrity is an issue as it is in cellulose analytics, it is recommended to replace DMSO by solvent components of similar solution behavior but without the inherent danger of generating oxidants, such as pyridine or DMAc, whenever possible.

Dimethyl(2-oxo-2-ferrocenylethyl)sulfonium iodide—a useful synthetic equivalent of ferrocenoylcarbene in the synthesis of ferrocene-containing cyclopropanes

The reaction of 1-ferrocenyl-3-thiabutan-1-one with methyl iodide in acetonitrile at room temperature gave dimethyl(2-oxo-2-ferrocenylethyl)sulfonium iodide, which was characterized by spectral data (¹H NMR, ¹³C NMR, IR) and X-ray crystallographic analysis. This salt reacted with a base (sodium hydride) in acetonitrile yielding a stabilized ylide—dimethylsulfonium ferrocenoylmethylide, which was in turn, submitted to reactions with seven conjugated enones. The obtained results showed that this methodology is potentially a new and useful approach to ferrocene-containing cyclopropanes.     

Sulfonium salts as prenyl, geranyl, and isolavandulyl transfer agents towards benzoylphloroglucinol derivatives

In search for new methods aiming biomimetic synthesis of polyprenylated acylphloroglucinols (PPAPs), we now report the results of an evaluation of sulfonium salts as prenyl, geranyl, and isolavandulyl transfer agents towards benzoylphloroglucinol derivatives, in neutral conditions. As a result, conditions were found for rather efficient C-prenylation of these compounds. The corresponding trimethyl ether gave the best results, but the reaction was accompanied by a deacylation process. Geranyl transfer was also observed, but in low yield, and, interestingly, an isolavandulyl group could be introduced with an appreciable yield.     

Syntheses and Crystal Structures of New Palladium(II) and Platinum(IV) Trialkylsulfonium Compounds

The reactions of platinum(II) iodide with triethyl‐ or trimethylsulfonium iodide in acetonitrile solution lead to the formation of crystalline products (Et₃S)₂[PtI₆] ( 1 ) and [Me₃S]₂[PtI₆]·CH₃CN ( 2 ), respectively. The formation of Pt(IV) complexes may be explained either by disproportionation of PtI₂ or oxidation by oxygen. Palladium(II) iodide reacts with triethylsulfonium iodide to give the palladium(II) complex (Et₃S)₂[PdI₄] ( 3 ). The crystal structures of 1 – 3 were determined by single‐crystal X‐ray diffraction. In the crystal structures, the compounds 2 and 3 exhibit an extensive hydrogen‐bonding network.