Synthesis, Reactivity and Structural Properties of Trifluoromethylphosphoranides.

Phosphoranides are interesting hypervalent species which serve as model compounds for intermediates or transition states in nucleophilic substitution reactions at trivalent phosphorus substrates. Herein, the syntheses and properties of stable trifluoromethylphosphoranide salts are reported. [K(18-crown-6)][P(CF ) ], [K(18-crown-6)][P(CF ) F], and [NMe ][P(CF ) F ] were obtained by treatment of trivalent precursors with sources of CF or F units.

Pentakis(trifluoromethyl)phenyl, a sterically crowded and electron-withdrawing group: synthesis and acidity of pentakis(trifluoromethyl)benzene, -toluene, -phenol, and -aniline.

A general route to functionalized pentakis(trifluoromethyl)phenyl (C6(CF3)5) derivatives, promising building blocks for designing novel stable carbenes, radical species, superacids, weakly coordinating anions and other practically and theoretically useful species, is presented. This pertrifluoromethylation route proceeds via conveniently pregenerated (trifluoromethyl)copper (CF3Cu) species in DMF, stabilized by addition of 1,3-dimethyl-2-imidazolidinone (DMI). These species react with hexaiodobenzene at ambient temperature to give the potassium pentakis(trifluoromethyl)phenoxide along with hexakis(trifluoromethyl)benzene and pentakis(trifluoromethyl)benzene in a combined yield of 80%.

Guanidinophosphazenes: design, synthesis, and basicity in THF and in the gas phase.

A principle for creating a new generation of nonionic superbases is presented. It is based on attachment of tetraalkylguanidino, 1,3-dimethylimidazolidine-2-imino, or bis(tetraalkylguanidino)carbimino groups to the phosphorus atom of the iminophosphorane group using tetramethylguanidine or easily available 1,3-dimethylimidazolidine-2-imine. Seven new nonionic superbasic phosphazene bases, tetramethylguanidino-substituted at the P atom, have been synthesized.

Noncyclic [10-S-5] sulfuranide dioxide salts with three S-C bonds: a new class of stable hypervalent compounds.

Phenyl triflate reacts with CF3SiMe3/Q+F- (Q+ = [K(18-crown-6)]+, Me4N+) and (Me2N)3S+Me3SiF2- to afford the first noncyclic [10-S-5] sulfuranide dioxide salts, [(CF3)3SO2]-Q+, with three S-C bonds, whose molecular structure was determined by X-ray crystallography.

Hexaalkylguanidinium and 2-(dialkylamino)-1,3-dimethylimidazolinium trimethyldifluorosiliconates and perfluoroalkoxides. Accidental isolation and molecular structure of [C(NMe2)3]+F-*6CH2Cl2.

Hexaalkylguanidinium and 2-(dialkylamino)-1,3-dimethylimidazolinium trimethyldifluorosiliconates, precursors for two stable hexaalkylguanidinium perfluoroalkoxides, were synthesized by treating commercially available bis(dialkylamino)difluoromethane derivatives with (dialkylamino)trimethylsilanes in aprotic media. With hexamethylguanidinium pentafluoroethoxide the introduction of the lipophilic and electronegative C2F5O group was straightforwardly achieved in the case of primary and secondary alkyl triflates to furnish the respective fluorinated ethers. The molecular structures of [(CH2NMe)2C(NEt2)]+[Me3SiF2]- and [C(NMe2)3]+F-*6CH2Cl2 were determined, showing in the latter case a fluoride anion octahedrally coordinated by six methylene chloride molecules via hydrogen bridges with a F.