Out-of-Plane Distortions in Fluorinated Nitrobenzene Radical Anions

According to the data of UHF/INDO calculations of the model conformations of fluorinated nitrobenzene radical anions, rotation of the nitro group relative to the plane of the benzene ring is accompanied by a pyramidal distortion of the group, which is of pseudo-Jahn–Teller nature. The degree of structural distortions depends on the position of the fluorine atoms in the benzene ring and on the solvent, increasing from DMF to DMF–water mixtures. The values of isotropic hyperfine interaction constants are interpreted in the series of fluorinated nitrobenzene radical anions, and the effects of water content in binary mixtures of solvents are discussed.     

Me2ESiMe3 (E = As,N, P) Compounds—Efficient Reagents for Replacement of the Fluorine Atom by Me2E Group in the Complex [(η6-1-F-3,5-Me2C6H3)(η5-C5EtMe4)Rh](CF3SO3)2 >

Russian Journal of Organic Chemistry -     

Selective hydrodechlorination of fluorinated arylamines

Chlorine-containing polyfluorinated anilines and meta-phenylenediamines undergo selective hydrodechlorination easily upon reduction by zinc in aqueous ammonia. A new approach is thus provided to synthetically valuable, partially fluorinated arylamines based on utilizing polyfluorochloroarenes, which are available as intermediates of perfluoroarene production from perchloroarenes. When chlorine atoms are present in positions both ortho and para to the amino group, para chlorine is initially eliminated. Based on this reaction, a one-pot synthesis of partially fluorinated 4-aminopyridines from 3,5-dichlorotrifluoro- and 3-chlorotetrafluoropyridine has been realized.     

Fluorine-containing carbocations. II. Polyfluorinated benzyl cations

When dissolved in SbF₅, polyfluorinated trifluoromethylbenzenes produce polyfluorinated α,α-difluorobenzyl ions. The ¹⁹F chemicals shifts and spin-spin coupling constants J(FF) have been analysed in terms of the resonance structures which contribute to the overall positive charge distribution. The influence of halogen atoms situated at position 4 on the downfield signal shift of α-fluorines follows the sequence F > Cl > Br which is opposite to that observed for 4-XC₆H₄CF₂⁺ ions.     

Radical-anions of meta-fluorobenzonitrile derivatives

Conclusion Cyclic polarometfy and ESR spectrometry were used to show that the introduction of fluorine atom into the meta position of benzonitrile leads to stabilization of the corresponding radical-anions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2794–2796, December, 1986.     

Reductive activation of arenecarbonitriles for the reactions with some carbon-centered electrophiles: the reaction mechanisms and synthetic applications

Synthetic and mechanistic aspects of the developed approach to the activation of aromatic nitriles are considered. The approach is based on the transformation of aromatic nitriles into stable anionic reduced forms. The latter, as shown for the reactions with alkyl halides and cyanoarenes, are promising reactants for the reactions with carbon-centered electrophiles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 754–765, April, 2008.     

Arene complexes of transition metals in reactions with nucleophilic reagents: XXX. Reaction of π-halomesitylene [Tetramethyl(ethyl)cyclopentadienyl]rhodium(II) complexes with anions derived from CH acids

Reactions of fluoro-and chloromesitylene π-complexes [(η⁶-1-Hlg-2,4,6-Me₃C₆H₂)(η⁵-C₅EtMe₄)Rh]-(BF₄)₂ (Hlg = F, Cl) with diethyl malonate anion in THF or acetone-d ₆ at 20°C initially (within the first 5–30 min) involve nucleophile addition at unsubstituted carbon atom in the arene ligand with formation of π-cyclohexadienyl complexes {[η⁵-1-(EtOCO)₂CH-1-H-3-Hlg-2,4,6-Me₃C₆H₂](η⁵-C₅EtMe₄)Rh}(BF₄). The subsequent replacement of the halogen atom yields {[η⁶-1-(EtOCO)₂CH-2,4,6-Me₃C₆H₂](η⁵-C₅EtMe₄)Rh}(BF₄)₂, where the arene ligand is readily withdrawn from π-coordination by the action of chloride ion or the solvent. Dimethyl mesitylmalonate was isolated in 76% yield. Likewise, the reactions with anions derived from malononitrile and ethyl cyanoacetate gave 25–38% of the corresponding derivatives 1-R-2,4,6-Me₃C₆H₂ where R = (NC)₂CH or EtOCO(NC)CH.