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.     

Alkylselenophosphonium salts

Conclusions Methylselenophosphonium salts have been obtained for the first time by the reaction of full amides of phosphoroselenoic and alkylphosphonoselenoic acids with methyl iodide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, p. 169, January, 1969.     

Synthesis of mono-amino-functionalised ferrocene, ferrocene salts and ferrocenium salts

A number of mono-amino-functionalised ferrocenes, ferrocene salts and a mono-amino-functionalised ferrocenium salt have been synthesised and characterised. This represents a novel method of accessing these important classes of molecules. In the cases of some of the ferrocene salts, there are some interesting structural features in the solid state. These include N-H...O and N-H...F hydrogen bonds.     

Pyridinium salts

New 4- (benzazol-2-yl)pyridinium salts have been synthesized. Their reduction in a neutral medium with sodium tetrahydroborate has given 2-(1,2,5,6-tetrahydropyridin-4-yl)benzazoles. The catalytic hydrogenation of the latter leads to piperidine derivatives which have also been synthesized by an independent route.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 104–107, January, 1974.     

Dioxolanium salts

A new method was developed for the synthesis of dioxolanium salts by the condensation of 1,2-glycols of the pinacol series with aliphatic acid anhydrides in the presence of perchloric acid. The dioxolanium ring is opened to form monoacylates of the starting pinacols under the influence of water, alcohol, and ammonia. A method was developed for the acetylation of aromatic compounds by dioxolanium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1023–1026, August, 1971.     

An efficient synthesis of imidazolinium salts using vinyl sulfonium salts

The synthesis of imidazolinium salts from the reaction of formamidines and (2-bromoethyl)diphenylsulfonium triflate is described. A variety of symmetrical and unsymmetrical imidazolinium triflate salts were synthesized in high yield in short reaction times under mild conditions. Aromatic and aliphatic N-substituents work well. The reaction is proposed to proceed via generation of a vinyl sulfonium salt intermediate from the bromoethylsulfonium triflate.     

Dialkyldialkoxyphosphonium salts

Conclusions Dialkyldialkoxyphosphonium halides are stable only in the case of branched alkoxy groups. The stability is explained by the difficulty of attack of the isoalkoxy group by halide anions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 415–417, February, 1971.     

Pentafluorosulfanylnitramide salts

The synthesis and properties of a new class of inorganic salts, named pentafluorosulfanylnitramide salts (or pentafluorosulfanylnitraminic acid salts) [Z+SF5NNO2-], are described. A number of SF5-nitramide salts (Z+SF5NNO2-) were successfully prepared via nucleophilic displacements from carbamates and/or ion exchange techniques, but some salts [M(SF5NNO2)x; M = Li, Mg, Al] decomposed during isolation procedures and appear to be unstable in the solid state. Single-crystal X-ray diffraction was used to fully characterize the Z+SF5NNO2-, and their properties/structures are compared with those of the corresponding dinitramide salts (or dinitraminic acid salts), Z+N(NO2)2-. X-ray crystallography revealed major structural differences between N(NO2)2- and SF5N(NO2)- salts concerning the N-N distances and the angles subtended at the central nitrogen atom. In the N(NO2)2- salts, there are two nonequivalent N-N (average lengths 1.372(2) and 1.354(2) A) distances and an average N-N-N angle of 115.8(3) degrees (falls between sp3 and sp2 hybridization). In the SFsNNO2- salts, the average N-N distance is much shorter, 1.308(9) A, and the average N-N-S angle is 120.0(5) degrees (closely fits sp2 hybridization). The SF5NNO2- salts show a remarkable metrical similarity for the SF5 moiety in all structures, indicating a lack of sensitivity to its steric and electronic environment. This is in marked contrast to N(NO2)2-, where there is a wide variation in conformations adopted by these anions which can be related to their environment.     

Aziridiniminium salts

Stable aziridiniminium salts have been obtained from the reaction of 2-amino-1-azirines with trityl tetrafluoroborate or trimethylsilyl triflate. These new derivatives of α-lactams react with carbanions to give 2-amino-1-aziridines.     

Thienopyrylium salts

The catalytic acylation and subsequent heterocyclization of- and-acetonyl derivatives of thiophene were studied. Mechanisms for the synthesis of thienopyrylium salts, the reaction of which with ammonia leads to the difficult-to-obtain thienopyridines, are proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 320–325, March, 1971.     

Pyranyltriphenylphosphonium salts

The reaction of pyrylium salts having a free or position with triphenylphosphine has given pyranylphosphonium salts. 2,4,6-Trisubstituted pyrylium salts do not react with triphenylphosphine. The properties and IR spectra of the compounds synthesized are discussed.     

Reactions of quinazolinium salts with quaternary heterocyclic salts yielding 3-hetarylquinolines

A novel type of transformations of the pyrimidine ring under the action of C-nucleophiles was found and a new method was developed for the synthesis of 3-hetarylquinolines from quinazoline derivatives and quaternary heterocyclic salts. An independent synthesis was carried out and transformations of one of the probable intermediates were studied. By-products were isolated. The effects of the nature of the heterocycle and substituents on the course of the ring transformation reaction were found, and the mechanism of the reaction was suggested. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1210–1215, June, 1998.     

Preparation of S-arylsulfoniacyclane salts

S-(4-Hydroxyaryl)sulfoniacyclane perchlorates have been obtained by the condensation of thiacyclanes with phenols in the presence of perchloric acid, phosphorus oxychloride, and hydrogen peroxide, or by condensing thiacyclane S-oxides under the same conditions but without the hydrogen peroxide. The capacity for forming sulfonium perchlorates decreases sharply in the sequence tetrahydrothiophene >thiacyclohexane>thiacycloheptane > methylthiacyclohexane; no sulfonium salts are obtained under these conditions from 2,2,6,6-tetramethylthiacyclohexane, 2-methyl-1-thiadecalin, or 2,5-dimethyltetrahydrothiophene. The S-(4-hydroxyaryl)sulfoniacyclane perchlorates take part in double-decomposition reactions, giving picrates, chlorides, and phosphates. The action of caustic potash in methanol on S-(4-hydroxyphenyl)tetrahydrothiophenium salt forms a dimeric sulfobetaine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1479–1482, November, 1973.     

Chemistry of N-fluoropyridinium salts

This tutorial review deals with developments in the chemistry of N-fluoropyridinium salts in the past decade, including both synthetic and mechanistic aspects. Three distinct types of transformations including: i) fluorination reactions, ii) carbenoid behavior and iii) cine-/tele- substitution involving N-fluoropyridinium cation are exemplified. Procedures for fluorination of carbanions and benzenoid aromatics along with hetarylation processes yielding 2- and 4-substituted pyridines are referenced. Several new discoveries in the area, including three-component condensation reactions of in situ generated N-fluoropyridinium fluoride are described.     

Synthesis of N-tetrahydropyranyl-S-methylmethioninesulfonium salts

D,L-Methionine reacts in alkaline medium with 4-methyl-3,4-epoxytetrahydropyran via the amino group to form, in accordance with the Krasusskii rule, an oxirane ring opening product, namely N-(4-hydroxy-4-methyl-3-tetrahydropyranyl)-D,L-methionine. N-(4-Hydroxy-4-methyl-3-tetrahydropyranyl)-S-methylmethioninesulfonium salts are synthesized in high yields by methylating the latter then treating it with organic or inorganic acids.Bashkir State University, Ufa. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 597–600, May, 1994. Original article submitted February 10, 1994.     

Hydroamination of pyrylium salts

The catalytic reductive amination of pyrylium salts proceeded stereoselectively to give piperidine bases with a cis-structure. The reaction involved the formation of a pyridine intermediate; the course of the reaction depended on the structure of both the substrate and the aminating agent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, 608–611, May, 1990.