Some novel oxime ethers. The synthesis of 1,1-difluoro-2-alkoxymethanimines

The syntheses of four novel 1,1-difluoro-2-alkoxymethanimines, RONCF₂, are reported. The oxime ethers are prepared in excellent yield by dehydrofluorination of the amines, RON(H)CF₃ (RCF₃, (CF₃)₂CF, CH₃, (CH₃)₃C) with KF. These oxime ethers are thermally stable at 24°C and are characterized by IR, NMR, and physical properties. The two perfluoro compounds undergo dimerization to give CF₃N(OR)CFNOR in the presence of CsF at room temperature.     

Darstellung von polyfluororganotrichlorsilanen

The following substances could be prepared by Grignard reactions or by conversions with trichlorosilane: C₆F₅CH₂CHCH₂, C₆F₅(CH₂)₃SiCl₃, CF₃(CF₂)₉CH₂CHCH₂, CF₃(CF₂)₇(CH₂)₂SiCl₃, CF₃(CF₂)₁₁(CH₂)₃CHCH₂ und CF₃(CF₂)₁₁(CH₂)₅SiCl₃.They were characterized by spectroscopical and microanalytical methods.     

Nitroxide chemistry. Part XIV [1]. Reactions of trifluoromethyl 2,3-dimethylbut-3-en-2-yl and trifluoromethyl 2,3-dimethylbut-2-yl nitroxides

The nitroxide CF₃N(?)CMe₂CMeCH₂ abstracts the aldehydic hydrogen from benzaldehyde, yielding the benzoyl compound PhCO₂N(CF₃)CMe₂CMeCH₂ (82%), the benzylic hydrogen from cumene, yielding PhCMe₂ON(CF₃)CMe₂CMeCH₂ (80%), and the methylene group hydrogen from fluorene, oxidises benzoin to benzil, and hydroquinol to quinone, attacks the Si'&'2.sbnd;H bond of trimethylsilane, and adds to tetrafluoroethylene to give the compound R¹N(CF₃)OCF₂CF₂ON(CF₃)R¹ (R¹ = CMe₂CMeCH₂, 97%), and to hexafluoropropene to give the 2:1-adduct.In a similar manner, the nitroxide CF₃N(?)CMe₂CHMe₂ adds to tetrafluoroethylene to give the compound R²N(CF₃)OCF₂CF₂ON(CF₃)R² (R² = CMe₂CHMe₂, 75%) and to hexafluoropropene to give a similar adduct (71%), and abstracts a benzylic hydrogen from toluene.     

Synthesis and some heterocyclisation reactions of CF2H- and CF2Cl-substituted 1,1-dicyanoethylenes

New CF₂X-analogues of 1,1-dicyano-2,2-bis(trifluoromethyl)ethylene (1) (X=H, Cl) were synthesised by the condensation of polyfluoroketones with malononitrile followed by dehydration using thionyl chloride (or phosphorus pentoxide). The heterocyclisation reactions of new CF₂X-analogues of 1,1-dicyano-2,2-bis(trifluoromethyl)ethylene with amidines, 5-aminopyrazoles and 3-methyl-2-pyrazolin-5-ones were systematically investigated.     

Action des perfluoroalkylcuivre(I) sur les perfluoroalkylethylenes

A series of new polyfluorinated dienes 3, containing the novel -CFCHCHCF-, pattern has been synthesized (50–70% yields) by reacting perfluoroalkyl iodides with perfluoroalkyl-ethylenes in the presence of copper. The monoalkenes R_fCFCHCH₂CF₂R′_f and the saturated compounds R_fCF₂CH₂CH₂CF₂R′_f were obtained by varying the experimental conditions. The ¹H and ¹⁹F NMR spectra are analysed and the reaction mechanism is discussed.     

Synthesis of allenes containing geminal trifluoromethyl groups

Allenes (CF₃)₂CCC(COOMe)₂ and (CF₃)₂CCC(COOEt) Ph were prepared by Cs-catalyzed condensation of octafluoroisobutene with dimethyl malonate and ethyl phenylacetate respectively. A stable salt

is formed from (CF₃)₂CCC(COOMe)₂ and CsF. Similar salts were prepared through the condensation of octafluoroisobutene with ethyl cyanoacetate and malononitrile. Allenes (CF₃)₂CCOMe₂ and (CF₃)₂CCCHPh were synthesized by dehydrofluorination of olefines (CF₃)₂CHCFCRR′ under the action of octafluoroisobutene and CsF mixture; the latter allene has been isolated only as a cycloadduct with octafluoroisobutene.     

Heterocyclic and acyclic derivatives of F-N-isopropylacetimidoyl chloride

$\text{F}$-N-Isopropylacetimidoyl chloride, CF₃CClNCF(CF₃)₂, has been used as a precursor for a variety of heterocyclic and acyclic compounds. Reaction with azide ion yields a mixture of the imidoyl azide, CF₃(N₃)CNCF(CF₃)₂, and the 1,5-tetrazole, CF₃$\text{CNNN}$CF(CF₃)₂. Hexafluoropropylideniminolithium produces as a minor product the conjugated diimine, (CF₃)₂CNC(CF₃)NCF(CF₃)₂, from nucleophilic attack at the imidoyl chlorine and as a major product the triimine, (CF₃)₂CNC(CF₃)NC(CF₃)₂NC(CF₃)₂, from further attack at the isopropyl fluorine. A thio-amide, CF₃C(S)NHCH(CF₃)₂, and a Δ³-1,2,4-dithiazoline, $\text{SSC(CF}{}_3\text{)NC}$(CF₃)₂, are produced upon reaction of hyrogen sulfide with the imidoyl chloride. Pathways are proposed for each of the reactions.     

Synthese regioselective de bases de mannich de cetones dissymetriques

Methods for the regioselective synthesis of Mannich bases starting from unsymmetrical ketones are described. The Mannich base on the more substituted carbon is obtained by reaction with (CH₃)₂N⁺CH₂,CF₃CO₂^- in CF₃CO₂H and its isomer on the less substituted carbon with (iPr)₂N⁺CH₂,ClO₄^- in CH₃CN. In the first case, the orientation corresponds to a non-selective attack of the immonium salt on a mixture of enols in which the more-substituted isomer is predominant. In the second ease, use of a bulky immonium salt induces a selectivity favoring the less-substituted enol.     

σ-Cumulenic transition metal compounds. Remarkably stable cobaloxime complexes; (R)2CCCHCo(dmg)2py

Interaction of NaCo(dmg)₂py with (R)₂CC(OSO₂CF₃)CCH in methanol provides a simple route to novel, stable cumulenyl complexes (R)₂CCCCHCo(dmg)₂py, where R = CH₃ or C₆H₅. In the case of R = H the stable ene-yne complex H₂CC(CCH)Co(dmg)₂py was isolated. The formation and properties of these complexes are discussed.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XI. Einige neuartige η1-vinyl-komplexe des eisens durch deprotonierung kationischer carbenkomplexe mit trimethyl(methylen)phosphoran

Novel η¹-vinyl complexes of the type Cp(CO)(L)FeC(OMe)C(R)R′ (R = R′ = H, Me; R = H, R′ = Me; L = Me₃P, Ph₃P) are obtainied via methylation of the acyl complexes Cp(CO)(L)FeC(O)R (R = Me, Et, i-Pr) with MeOSO₂F and subsequent deprotonation of the resulting carbene complexes [Cp(CO)(L)FeC(OMe)R]SO₃F with the phosphorus ylide Me₃PCH₂. The same procedure can be applied for the synthesis of the pentamethylcyclopentadienyl derivative C₅Me₅(CO)(Me₃P)FeC(OMe)CH₂, while treatment of the hydroxy or siloxy carbene complexes [Cp(CO)(L)FeC(OR)Me]X (R = H, Me₃Si; X = SO₃CF₃) with Me₃CH₂ results in the transfer of the oxygen bound electrophile to the ylidic carbon. Some remarkable spectroscopic properties of the new complexes are reported.     

Fluoroalcohols as solvents for aliphatic polyamides

Some fluoroalcohols have been prepared by free-radical addition of methanol, ethanol and isopropanol to fluoroolefins as C₃F₆, CFHCFCF₃, (CF₃)₂CFCFCFCF₃, H(CF₂)₄CFCF₂, The general reaction is (1) R_fCFCF₂ + RR′CHOH = R_fCFHCF₂CRR′OH where R_f is a fluoroalkyl group, R and R′ are H or CH₃. NMR data of these alcohols are reported. 2,2,3,4,4,4-hexafluorobutanol (HFB) shows the best solvent ability among the compounds of this class. Its properties and solvent power have been evaluated and compared to the ones of trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP). Some toxicological data related to HFB, TFE and HFIP are also reported.Owing to their strong tendency to form hydrogen bonds, fluoroalcohols are excellent solvents for polymeric materials which possess receptive sites for hydrogen bonding formation. The bonding power of the OH has been investigated by IR and NMR Spectroscopy on amide-group containing substrates. The properties and the correlations observed have pointed out that HFB may be usefully used as solvent for some aliphatic polyamides as Nylon 6.The polymer-solvent system Nylon 6-HFB has been studied and the constants of Mark-Houwink equation determined.     

Triphenyltelluronium β-diketonates; Synthesis and spectra

Triphenyltelluronium /gb-diketonates, RC(O)CHC(O)R¹ (where R = CH₃, Ph or CF₃ and R¹ = CH₃, Ph, CF₃ or 2-thienyl) have been prepared. Spectral data(IR, ¹H and ¹³C NMR, mass spectroscopy) are presented and discussed in conjunction with molecular weight and conductivity data. It is concluded that weak coordination of the β-diketonate to the tellurium atom is a common structural feature of the compounds.     

Preparation of ferrocenes with high fluorous-phase affinities

The reaction of 1,1′-bis(pentafluorophenyl)ferrocene with fluorous alkoxides having the general formula NaOCH₂(CF₂)_nCF₃ (n = 0, 2, 5, 7, and 8) afforded a series of ferrocenes of general formula {η⁵-4-[CF₃(CF₂)_nCH₂O]C₆F₄C₅H₄}₂Fe (1). The reaction of 1,1′-bis(4-tetrafluoropyridyl)ferrocene with the same fluorous alkoxides afforded a series of ferrocenes of general formula (η⁵-4-{2,6-[CF₃(CF₂)_nCH₂O]₂C₅F₂N}C₅H₄)₂Fe (2). Perfluoro(methylcyclohexane)/toluene partition coefficients increase with the number (2 or 4) and length (n) of the fluorous substituent. Complexes 1a and 2a (both n = 0) were structurally characterized.     

Isocyanide insertion into platinumoxygen bonds

The reaction of isocyanides, CNR, with hydroxy- and methoxy-alkyl complexes of platinum(II), PtOH(R)(Ph₂ PCHCHPPh₂)_and PtOCH₃(R)(Ph₂PCHCHPPh₂) (R  CF₃, CH₂ CN) affords insertion products Pt(CONHR)(R)(Ph₂PCHCHPPh₂) and Pt[C(OCH₃)NR] (R)(Ph₂PCHCHPPh₂) containing the carboxamido and imidoyl moiety, respectively.     

Siliconcarbon multiple-bonded (pπpπ)intermediates : II. Chemical reactivity and selectivity of thermally generated 1,1-dimethyl-1-silaethene (Me2SiCH2)

The order of reactivity and the selectivity of 1,1-dimethyl-1-silaethene (Me₂SiCH₂), generated from 1,1-dimethylsilacyclobutane at 611°, toward a variety of substrates was determined using standard competition experiments. The observed reactivity order was Ph₂CO>ROH, ArOH ? m-ClPhNH₂ CH₃CN, which indicates that with these substrates and under the reaction conditions used, Me₂SiCH₂ is behaving like an electrophilic species. Within a given class of substrates, polar effects were found to be generally unimportant, while increased steric effects caused a decrease in rate (up to 50%).     

Die ersten CF3-substituierten organyl(chlor)silane

The three component reaction (Et₂N) ₃P/CF₃Br/ R_nSiCl_4-n (n = 1,2,3; RCH₃,Ph) gives CF₃-substituted organyl(chloro)silanes for the first time. Their genesis will be elucidated.     

Some diels—alder reactions of η1-bonded cyclopentadienylmetal compounds

Bis(cyclopentadienyl)mercury readily undergoes Diels—Alder reactions with RCCR (R = CO₂Me or CF₃), CF₃CFCFCF₃, CF₃CFCF₂, (CF₃)₂CC(CN)₂, C₂(CN)₄ and Ph$\text{NCONNC}$O to give stable adducts characterised by¹H, ¹⁹F and ¹³C NMR, spectroscopy. Similar reactions of CF₃CCCF₃ and CF₃CFCFCF₃ with the cyclopentadiene derivatives Me₃MC₅H₅ and (Me₃M)₂C₅H₄ (M = Si, Sn) are also described.     

Phospha-s-triazines II. Mass spectra of mono(diarylphospha)-s-triazines

Electron impact fragmentation patterns were obtained for 1-dephenylphospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine, 1-diphenylphospha-3,5-bis[C₃F₇(OCF(CF₃)CF₂)_xOCF(CF₃]-2,4,6-triazine (x=1 and 2) and their pentafluorophenyl analogues. In each instance the ion R₂PN₂C⁺ (RC₆H₅ or C₆F₅) constituted the base peak. Based on the observed metastable peaks, fragmentation pathways leading to the formation of this and other significant ions are postulated and similarities to s-triazine and diphenyl phosphazene trimer breakdown patterns are discussed.     

gem-Difluoroallyllithium: Preparation by the transmetalation procedure and some reactions

3,3-Difluoroallyltrimethyltin has been prepared by the reaction of β-trimethylstannylethylidenetriphenylphosphorane with chlorodifluoromethane. This tin compound reacts with n-butyllithium in tetrahydrofuran at -95°C to generate gem-difluoroallyllithium. The latter, however, is not stable in solution at that temperature. If generated in situ in the presence of a triorganochlorosilane, products of the type R₃SiCF₂CHCH₂ are obtained in good yield. Addition to the CO bond of 3-pentanone to give (C₂H₅)₂C(OH)CF₂CHCH₂ was achieved by the method of alternate, incremental additions.     

Halomethyl-metal compounds : LIX. An Improved preparation of phenyl(fluorodichloromethyl)mercury,a useful fluorochlorocarbene precursor

An improved procedure for the preparation of phenyl(fluorodichloromethyl)mercury involving the reaction of phenylmercuric chloride with sodium methoxide and fluorodichloromethane in THF/methanol at ?40° is described. This procedure gives PhHgCCl₂F in high yield and generally of about 85% purity. Reactions of the PhHgCCl₂F thus prepared with olefins [cyclohexene, cyclooctene, allyltrimethylsilane, vinyltriethylsilane, Me₂CCHCl, Me₂CC(Br)Me, CH₂C(Me)CH₂Cl and norbornene] gave the expected cyclopropanes in high yield. This mercury reagent added CClF to the CN bond of PhNCCl₂, giving 1-phenyl-2-fluoro-2,3,3-trichloroaziridine and to the CS bond of thiobenzophenone. The thiirane formed was, however, unstable to the reaction and work-up conditions and only its desulfurization product, Ph₂CCClF, could be isolated. Fluorochlorocarbene transfer from this mercurial also could be induced by the action of sodium iodide in DME. Evidence is presented which shows that PhHgCCl₂F is more reactive in CClF transfer than indicated in a previous report.