Reactions of F-propene and its dimer with sodium dialkyldithiocarbamate

Sodium dialkyldithiocarbamates readily attacked $\text{F}$-propene to give S-(1,1,2,3,3,3-hexafluoropropyl)-N,N-dialkyldithiocarbamates, CF₃CHFCF₂SC(S)-NR₂, and $\text{Z}$ and $\text{E}$-S-(1,2,3,3,3-pentafluoropropenyl)-N,N-dialkyldithiocarbamates, CF₃CFCFSC(S)NR₂. The pyrolysis of the former compound quantitatively gave the dialkylthiocarbamoyl fluorine, R₂NC(S)F, while the latter compound and sodium tetraphenylborate formed the corresponding 1,3-dithiolan-2-ylium tetraphenylborate. $\text{F}$-2-Methyl-2-pentene also reacted with sodium dialkyldithiocarbamate to give (CF₃)₂CHC[SC(S)NR₂]CFCF₃. The mechanism of this reaction is supposed to involve a 1,4-RSF-elimination.     

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.     

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.     

Determination de la structure de perfluoroalcenes a chaines longues par R.M.N. du 19F 2éme Partie : Perfluoroalcenes 2–3 et 4

The fluoride ion induced isomerisation of 1-perfluoroalkenes R_FCFCF₂ (R_F=C₄F₉, (I) -C₅F₁₁ (II), -C₆F₁₃ (III), -C₇F₁₅(IV) has been studied in the polar solvents DMF and VMSO. The reaction gives a mixture which changes to the thermodynamically stable isomer. ¹⁹F n.m.r. spectroscopy allows characterisation of products and shows that all alkenes formed are $\text{cis}$-derivatives. The products formed are explained on the basis of a cyclic intermediate involving participation of the metal cation.     

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.     

Reactions of mesomeric fluorocarbanions with acid anhydrides. Transformation of trifluoromethyl groups into fluorocarbonyl and perfluoroacyl groups

It was found that the reaction of mesomeric fluorocarbanions of the CF₃$\text{C}\text{θ}$XCOY type with benzoic anhydride leads to the loss of benzoyl fluoride and the formation of mesomeric carbanions of the FCO$\text{C}\text{θ}$XCOY type. In a similar reaction with perfluorocarboxylic acid anhydrides, besides a CF₃→COF transformation, further change of COF into COR_F is observed, leading to the formation of salts containing mesomeric anions of the R_FCO$\text{C}\text{θ}$XCOY type, which, upon acidification, give 1,1- -bis(perfluoroacyl)-2,2,2-trifluoroethanes CF₃CH(COR_F)₂ , tris- (perfluoroacyl)methanes (R_FCO)₃CH and bis(trifluoroacetyl)- acetic ester (CF₃CO)₂CHCOOMe. It has been shown that perfluoroalkyl groups in β-diketones and β,β′-triketones may hinder enolization despite their electron-attracting effect.     

Nuclear magnetic resonance spectra of polyfluorobuta-1,3-dienes. Part II [1]. Variable temperature study of two 2-azabutadienes

The two perfluoro-azadienes CF₂N.CRCF₂ (R = CF₃ or CF₂Cl) show temperature dependent ¹⁹F n.m.r. spectra, with non-equivalent fluorine nuclei of the CF₂N portion at low temperatures, which coalesce due to inversion at the nitrogen at higher temperatures (ΔG3 = 60 kJ mol^?1). N.m.r. parameters have been obtained. One of the five-bond FF coupling constants is much larger ($\text{ca}$. 24 Hz) than the remainder (0·5–5·5 Hz), possibly due to ‘through-space’ coupling of fluorines in the $\text{cis}$-skew conformation.     

Adventures with azides of the fluorocarbon class

Mechanistic and synthetic highlights of out studies during the past twenty years on azides derived from fluorocarbon systems {alkenes ($\text{e.g.}$ CF₃CFCFN₃), aza-alkenes and -cycloalkenes [$\text{e.g.}$$\text{CF}{}_2\text{(CF}{}_2\text{)}{}_2\text{C(CF}{}_3\text{)NC}$(CF₃)N₃], arenes ($\text{e.g.}$ C₆F₅N₃), and heteroarenes($\text{e.g.}$ 4-N₃.C₅F₄N)} will be discussed with emphasis on recent results bearing on the synthesis of novel seven-membered $\text{N}$-heterocycles.     

Some approaches to the synthesis of fluorinated alcohols and esters. II. Use of F-alkyl iodides for the synthesis of F-alkyl alkanols

Free radical addition of an F-alkyl iodide (R_FI) to an alkenol or ester, followed by appropriate reduction is an efficient method for preparing the corresponding F-alkyl-alkanols of the homologous series, R_F(CH₂)_n?OH. When n = 2,4 or higher, the two steps take place smoothly. The 1,2,3-substituted systems R_FCH₂CHYCH₂Z, however, are susceptible to surprising difficulties. Reduction of R_FCH₂CHICH₂ON to R_F(CH₂)₃OH by hydrogen and catalyst (strong base acid acceptor), can be done either in one step or $\text{via}$ R_FCHCHCH₂OH; however, dehydrohalogenation may also give the epoxide, and reduction in this case leads to the secondary alcohol, R_FCH₂CH(CH₃)OH. By contrast, reduction of R_FCH₂CHICH₂OAc by tributyltin hydride or with hydrogen over palladium (diethylamine acid acceptor) goes smoothly. Zinc and acid reduction of R_FCH₂CHICH₂OAc gives elimination to R_FCH₂CHCH₂; even R_FCHCICH₂OH gives R_FCHCCH₂ besides R_FCHCHCH₂OH. R_FCHCICH₂CH₂OH, however, with zinc and acid is reduced cleanly to R_FCHCHCH₂CH₂OH.     

Syntheses of σ-cyclobut-1-en-3-onyl complexes by cycloaddition of ketenes to some transition metal alkynyl complexes

Reactions of ketenes (R¹R²CCO) with (η⁵-C₅H₅)Ni(PPh₃)CCR (I) and (η⁵-C₅H₅)Fe(CO)(L)CCR (III, L = CO and PPh₃) give σ-cyclobut-1-en-3-onyl complexes, {(η⁵-C₅H₅)Ni(PPh₃)$\text{CC(R)COC}$}R¹R² (VI) and (η⁵-C₅H₅)Fe(CO)(L)$\text{CC(R)COC}$R¹R² (IX)}, (2 + 2) cycloaddition products, in good yields. The σ-cyclobutenonyl complexes also can be prepared by the reaction of I and III with acyl chlorides in the presence of triethylamine.     

Determination de la structure de perfluoroalcenes a chaines longues par R.M.N. du19F : lère Partie : pefluoroalcenes-1

After a review of 1-perfluoroalkene R_FCFCF₂ synthesis, with R_FC₄F₉, C₅F₁₁, C₆F₁₃, we have studied their fine structures by ¹⁹F N.M.R. This study has led us to first generalize the rules set for the chemical shifts and coupling constants of olefinic fluorine atoms of fluoropropene and their derivatives. Then, we have been able to determinate unambiguously the chemical shifts of the difluoromethylene groups of the perfluorinated chains. We have thus shown, by irradiation, that inversions may take place in the chemical shifts of the CF₂ groups at the β and γ position of the double bond.     

Synthesis and reactions of fluorinated iminium salts

Different methods for the preparation of fluorinated iminium salts RR¹CNR²R³⁺MF₆^? (R=R¹=F ; R²=R³=CH₃, C₂H₅ M=As, Sb 4a ? c R=H, R¹=F; R²=R³=CH₃ M=As, Sb 5a, b R=R¹=CF₃; R²=H, R³=CH₃ M=Sb 12 R=R¹=CF₃; R²=R³=CH₃ M=As 14) are reported, the spectroscopic properties (IR, NMR) of the cations of these salts are briefly discussed. By F^?-addition to these salts, $\text{e.g.}$ to 16, perfluoroalkyl-bis(alkyl)-amines ($\text{e.g.}$ (CF₃)₂CFN(CH₃)₂ 15) can be prepared; from the methylation of CF₃NCF₂ bis(trifluoromethyl) methylamine (CF₃)₂NCH₃ (11) was obtained.     

Reactivity of perfluoroalkenylmagnesium halides : Application to the synthesis of new α-β unsaturated polyfluorinated alcohols and organometallic compounds

The reactivity of perfluoroalkenylmagnesium bromides R_FCFCFMgBr (R_FC₄F₉, C₆F₁₃), obtained from the corresponding l-bromo-perfluoroalkenes, has been investigated.These Grignard reagents react with carbonyl compounds to give, with good yields, a series of new α-β unsaturated polyfluorinated alcohols R_FCFCFC(OH)RR′ (1). The synthesis and spectrographic characteristics of these compounds are reported and discussed.Perfluoroalkenyl mercuric and tin derivatives are obtained from the reaction of the perfluorinated Grignard reagents with mercuric salts and organotin halides respectively :

Spectroscopic identification and some chemical properties of these new perfluorinated organometallic compounds are given.The good reactivity of these unsaturated derivatives towards protic acids and electrophiles, leading to the cleavage of the perfluoroalkenyl group, is used to study the possibilities of transmetallation reactions.Somes examples of these reactions are reported.     

Amino-sulphur-fluorine derivatives as fluoride ion donors: preparation of three- and four-coordinated cations of sulphur (IV) and (VI) [1,2]

Pentacoordinated aminosulphur (IV) trifluorides, R₂N$\text{S}$F₃, (in this paper the lone pair in S(IV)-derivatives is always considered as a ligand) and aminosulphur(VI)-oxidetrifluorides, R₂NS(O)F₃, readily lose a fluoride ion to Lewis acids (AsF₅, SbF₅, BF₃) to give sulphur-containing cationic species [R₂N$\text{S}$F₂]⁺ and [R₂NS(O)F₂]⁺ with tetracoordinated sulphur. Tetracoordinated neutral dialkylaminosulphur(IV)-oxidefluorides, R₂N$\text{S}$(O)F, and amino-imino sulphur(IV)fluorides, R₂N$\text{S}$(=NR_f)F, give three-coordinated sulphur cations [R₂N$\text{S}$O]⁺] or [R₂N$\text{S}$NR_f]⁺.The three-coordinated sulphur(VI)cation [R₂NS(O)NR]₊ has also been formed.     

Some reactions of 1,2,3,4,7,7-hexafluorobicyclo[2,2,1]hepta-2,5-diene: Thermolysis and attack by methoxide ion and by bistrifluoromethyl nitroxide

1,2,3,4,7,7-Hexafluorobicyclo[2,2,1]hepta-2,5-diene gave 1,2,3,4-tetrafluorebenzene in at least 73% yield when heated to 450°C in a sealed tube; the CF₂ bridge appeared, in part, as octafluorocyclobutane. Nucleophilic attack by sodium methoxide- methanol on the diene occurred exclusively at the CFCF bond, causing the formation of 1,2,4,7,7-pentafluoro-3-methoxybicyclo- [2,2,1]hepta-2,5-diene and a 1,4,5,6,7,7-hexafluoro-5-methoxybicyclo [2,2,1]hept-2-ene thought, on the basis of ¹⁹F nmr data, to be the 6-$\text{endo}$-F,5-$\text{exo}$-MeO isomer. Radical attack on 1,2,3,- 4,7,7-hexafluorobicyclo[2,2,1]hepta-2,5-diene by bistrifluoromethyl nitroxide took place at both olefinic sites, with a $\text{ca}$. 10:1 preference for the CFCF linkage; all three geometrical isomers of 5,6-bis(bistrifluoromethylamino-oxy)-1,4,5,6,7,7- hexafluorobicyclo[2,2,1]hept-2-ene were formed.     

The reaction of perfluoro-2,4-dialkyloxolanes with anhydrous aluminum chloride

Several kinds of perfluoro-2,4-dialkyloxolanes (A), having such alkyl groups as R_fR′_fCF₃ (2a); R_fC₂F₅, R′_fCF₃ (3a); R_fCF₃, R′_fC₂F₅ (4a); R_fR′_fC₂F₅ (5a); R_fCF₃, R′_fnC₃F₇ (6a) on the 2 and 4 positions of the oxolane ring, respectively, were treated with AlCl₃ in a heterogeneous reaction to give the corresponding perfluoro-2,5,5-trichloro-2,4-dialkyloxolanes (B). For purposes of comparison, the respective reactions of perfluoro-2-methyl-oxolane (la), perfluoro-2-n-butyloxolane (7a), and perfluoro-2, 5-dimethyloxolane (8a) with AlCl₃ were also conducted. An increasingly higher reaction temperature was needed for the reaction of A with AlCl₃ to give B as the carbon number of A increased. Cis- and trans-perfluoro-4-chloro-2,4-dimethyl-γ-butyrolactones (2c) were obtained from the hydrolytic reactions of cis- and trans-perfluoro-2,5,5-trichloro-2,4-dimethyloxolanes (2b), respectively, with fuming H₂SO₄. Physical properties and ¹⁹F nmr data are given for these new compounds.     

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.     

Some partially fluorinated cyclic and acyclic compounds of sulphur (II) and (IV) and partially fluorinated cyclic compounds of phosphorus (III) and (V)

Sulfinyl fluoride and N-(F-isoprophyl)iminosulfur difluoride form the compounds, O$\text{SN(CH}{}_3\text{)CH}{}_2\text{CH}{}_2\text{N}$(CH₃) and i-C₃F₇N$\text{SN(CH}{}_3\text{CH}{}_2\text{CH}{}_2\text{N}$(CH₃ with symdimethylethylenediamine (1). In contrast, CF₃C(O)NSF₂ and (R_f)₂SF₂ (R_f = CF₃, i-C₃F₇ form only acyclic compounds, CF₃C(O)N(CH₃)CH₂CH₂N(CH₃)C(O)CF₃ and R_fSN(CH₃)CH₂CH₂N(CH₃)SR_f with (1). With PF₃, PF₅ and OPF₃, cyclic compounds $\text{N(CH}{}_3\text{)CH}{}_2\text{CH}{}_2\text{N(CH}{}_3\text{)P}$F, $\text{N(CH}{}_3\text{)CH}{}_2\text{CH}{}_2\text{N(CH}{}_3\text{)P}$F₃, and $\text{N(CH}{}_3\text{)CH}{}_2\text{CH}{}_2\text{N(CH}{}_3\text{)P}$-(O)F result. When the latter two compounds are reacted further with LiNC(CF₃)₂, N(CH₃)CH₂CH₂N(CH₃)PF₂NC(CF₃)₂ and $\text{N(CH}{}_3\text{CH}{}_2\text{CH}{}_2\text{N(CH}{}_3\text{)P}$(O)NC(CF₃)₂) form.     

Synthese d'acides perfluores de hauts poids moleculaires

Perfluorinated olefins of general formula CF₃(CF₂)_pCFCF(CF₂)_mCF₃ (3 ? m + p ? 25) are oxidized by potassium permanganate or ruthenium tetroxide. The linear high molecular weight perfluorinated carboxylic acids so obtained are characterized by ¹⁹F N.M.R. spectroscopy.     

The crystal and molecular structure of bis(triphenylsilicon) carbodiimide

The structure of (Ph₃SiN)₂C has been determined by single crystal X-ray diffraction. The structure was solved by direct methods and refined to R = 0.071 for 593 independent diffractometer data. The crystals are rhombohedral, R$\text{3}$ with a = b = c 18.201(20) Å, α = β = γ = 48.82(2)°, and Z = 4. The three crystallographically independent molecules each have linear SiNCNSi chains lying along the crystallographic threefold axes; in two of the molecules the central carbon atom lies on a centre of symmetry. Principal mean bond lengths and angles are: Si, 1.696(25); SiC, 1.846(20); NC, 1.164(30); CC, 1.387(14) Å; CSi, 108.2(6); and CSiC, 110.8(6)°.