Radical addition of methyldichlorosilane to vinyl acetate

The GC-MS method was used to identify the addition products of methyldichlorosilane to vinyl acetate. Radiation-induced addition of methyldichlorosilane to vinyl acetate produces 2-methyldichlorosilylethyl ethyl ether. The reaction follows a radical-chain mechanism. The ratio of the rate constants of methyldichlorosilyl radical addition to C=C and C=O to vinyl acetate amounts to 0.4±0.1 (303 K).

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- . , - 2- . , C=C C=O 0,4±0,1.

     

Synthesis of cyclopentanoid natural products via vinyl phosphonium salts

Cyclopentenones obtained from cyclisations involving phosphonium salts are converted to dihydrojasmone, dihydrojasmolone and known precursors of methylenomycins A and B.     

Radical addition of secondary phosphine sulfides and selenides to vinyl tellurides

The regiospecific addition of secondary phosphine sulfide and phosphine selenide to alkyl vinyl tellurides proceeds under radical initiation (AIBN, 65–70 °C, 2.5–3.5 h) to afford the anti-Markovnikov adducts, (2-alkyltellanylethyl)phosphine chalcogenides, in 86–99% yields.     

Ammonium phosphonium salts

Conclusions Ammonium phosphonium salts are formed when tertiary phosphines are reacted with benzalaniline in the presence of dry HCl.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 719–720, March, 1984.     

Radical addition of thiols to vinyl derivatives of 4,5-diphenylimidazole-2-thione

It is shown that 2-vinylthio- and 1-vinyl-2-vinylthio-4,5-diphenylimidazoles readily add thiols to the double bond of the vinyl group attached to the sulfur atom. A vinyl group attached to the nitrogen atom undergoes only 7–15% thiylation; this is explained by the electron-acceptor effect of phenyl groups and also by steric factors.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1554–1556, November, 1976.     

Nickel-catalyzed synthesis of phosphonium salts

The nickel-catalyzed synthesis of phosphonium salts from aryl halides and triphenylphosphine is reported.The formation of phosphonium salts occurs by the oxidative addition reaction of Ni[P(C₆H₅)₃]₃ on the aryl halides and reaction of the coordinated aryl groups with triphenylphosphine.The influence of substituents on the aromatic nucleus is studied.     

Phosphite addition to organometallic cations to give phosphonium adducts

Addition of tri-n-butylphosphite to [(C₆H₇)Fe(CO)₃]BF₄, [(C₆H₆OMe)-Fe(CO)₃]BF₄, and [(C₇H₇)Cr(CO)₃]BF₄ has yielded novel phosphonium salts; which are remarkably stable.     

Solvent-free mechanochemical synthesis of phosphonium salts

Phosphonium salts have been prepared during high-energy ball-milling of triphenylphosphine with solid organic bromides; the reactions occur at ambient conditions without a solvent; in the case of 2-bromo-2-phenylacetophenone the reaction in a solution usually produces a mixture containing both the C-phosphorylated and O-phosphorylated compounds, while the solvent-free mechanically induced transformation results in the thermodynamically favorable C-phosphorylated product; the occurrence of the observed transformations during mechanical processing of solid reactants is confirmed by the solid-state 31P NMR spectroscopy and X-ray powder diffraction.     

Preparation and synthetic utility of fluorinated phosphonium salts,bisphosphonium salts and phosphoranium salts

The synthesis and mechanism of formation of phosphonium salts of the type [R₃$\text{P}\text{+}$CFXY]Z^? (where X = F, Cl, Br; Y = Br, Cl; Z = Br, Cl), $\text{bis}$-phosphonium salts of the type [R₃$\text{P}\text{+}$CF₂$\text{P}\text{+}$R₃]2Br^?, and phosphoranium salts of the type [R₃$\text{P}\text{+}$$\text{C}\text{?}$F$\text{P}\text{+}$R₃]X^? (X = Br, Cl) will be presented. The applicability of these substrates in the generation of useful nucleophilic or electrophilic synthetic intermediates will be discussed.     

Preparation and application of functional polymers—II. Preparation of vinyl ethers and thioethers using polymer-supported phosphonium salts

Insoluble polystyryldiphenyl-methoxymethyl- and methylthiomethyl-phosphonium chlorides have been prepared by treating polystyryldiphenylphosphine with chloromethylmethyl-ether and thioether respectively. These reagents were used for the conversion under mild conditions of carbonyl compounds into vinyl-ethers and thioethers, otherwise difficult to obtain; yields are high and work-up is easy. Moreover, methyl and ethyl β-styryl ethers were also prepared from the polymeric phosphorane by treatment with formate esters.     

Visible light-induced thiocyanation of gem-difluorinated phosphonium salts

gem-Difluorinated phosphonium salts were generated from nitrones by methylation and reaction with (triphenylphosphonio)difluoroacetate. The phosphonium salts were subjected to visible light-induced phosphonium–thiocyanate exchange in the presence of ammonium thiocyanate, copper thiocyanate, and an iridium photocatalyst. The sequence of the reactions was performed in one pot affording thiocyanates attached to the difluoromethylene fragment.     

Versatile approach to naphthoquinone phosphonium salts and evaluation of their biological activity

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Phase-transfer reactions catalyzed by phosphonium salts bound to macroporous polystyrene supports

The rate of reaction of alkyl halides with aqueous sodium acetate or cyanide catalyzed by phosphonium salts supported on insoluble polystyrene resins, and rates of ion-exchange of the chloride ion in the catalysts against the acetate ion, were studied as a function of catalyst particle size, the percentage of ring substitution, the morphology of polymer support, and distance between active site and polymer backbone. Rates of 1-bromooctane or benzyl chloride with macroporous, 7–25% ring-substituted catalysts increased with increasing ring substitution. Rates with macroporous catalysts increased as a heptamethylene spacer was introduced between the active site and the polymer backbone. Rates of ion-exchange with macroporous catalysts were facilitated with increasing ring substitution or by the introduction of the spacer chain. A relation between the catalytic activity of macroporous or microporous catalysts and ion-exchange rates under triphase conditions was discussed.     

Radical addition of methyldichlorosilane to ketones

Radiation-induced reaction of methyldichlorosilane with ketones is shown to form products of radical addition to the carbonylic group. Competition kinetics method was used to determine relative rate constants of methyldichlorosilyl radical addition to some ketones.

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