Anion stabilization,by sulfur

Notice that arrows both start and stop on the sulfur atom, which changes from S(II) to S(IV) during the reaction. The new functional group with an S 0 bond is called a sulfoxide. This is j a good preparation of allylic sulfoxides. The ph/ product forms an anion stabilized by sulfur, which can be alkylated. 

The process represented by V — IV occurs, however, in the solvolysis of a preionized material, such as triethyloxonium fluorophosphate, which was employed by Kevill and Lin (21) to establish a scale of nucleophilicity parameters, N. Because the effect of variable anion stabilization by solvent was not subtracted, whether their N values measure true and only nucleophilic reactivities is uncertain. This doubt would be dispelled, however, by an experiment in which the reagent would be treated with small amounts of nucleophile in a better anion-stabilizing solvent, such as TFA, or even sulfuric acid. 

Nucleophilic Substitutions. 7V,7V-Dimethyldithiocarbamoyl-acetonitrile (1) serves as an active methylene compound, because its carbanion is stabilized by sulfur and cyano groups. It can be alkylated stepwise in aqueous sodium hydroxide under phase transfer catalysis (eq 1). The anion undergoes nucleophilic aromatic substitution to give nitroarenes, with elimination of the dithiocarbamate group (eq 2). Nucleophilic addition of (1) to phenyl isothiocyanate also occurs readily. ... 

In general sulfur ylide-mediated epoxidation cannot be used to form an epoxide with an adjacent anion-stabilizing group such as an ester, as the requisite ylide is too stable and does not react with aldehydes [23], With the less strongly electron-withdrawing amide group, however, the sulfur ylide possesses sufficient reactivity for epoxidation. The first example of an asymmetric version of this reaction was by... 

The Ag cations are coordinated to two sulfur atoms of different cavitands with Ag-S distances in the range 2.47-2.50 A. In the solid, efficient r-stack-ing of the P-phenyl groups with the picrate anions stabilizes the supramolecular complex (Fig. 10). The two cavitands are aligned along their common C4 axis and offset by about 45°, leading to a helical structure. The inner space is reduced by the occupancy of the sulfur atoms, and there is probably not enough room to accommodate small guests inside the cavity. 

Organolithiums have been shown to add to a variety of trithiocarbonate oxides exclusively in a thiophilic maimer, as a consequence of the electrophilic character of the sulfine sulfur, to give an intermediate carbanion stabilized by three sulfur atoms the soft carbanion, which forms trithioorthoester oxide on quenching with water, acts as the equivalent of the (alkylthio)carbonyl anion in Michael addition.98... 

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