Reactions of perfluoronitriles. II. Interactions with phenylphosphine

Treatment of perfluoro-n-octanonitrile with phenylphosphine gave tetraphenyltetraphosphine and a spectrum of reduction and interaction products. Fifteen compounds were identified. The imine, (R_fC₇F₁₅) R_fCHNH, and the amine, R_fCH₂NH₂, were the primary reduction products. Secondary phosphorus-free products, some formed following ammonia evolution, were the following: R_fCHNCH₂R_f, R_fCH₂CH(NH₂)R_f, R_fC(NH)NCR_f(NH₂), R_fCH₂NHCR_f(NH), (R_fCN)₃, R_fCHNCR_fNCR_f(NH), R_fCH₂NCR_fNHCH₂R_f, and R_fCH₂NCR_fNHCR_f(NH). Only three phosphorus-containing materials were definitely identified: R_fCH(NH₂)P(C₆H₅)H, R_fCH[P(C₆H₅)H]NCHR_f, and R_fC(NH)P(C₆H₅)CR_f(NH). Depending on reaction conditions, specific phosphorus-containing compounds could be preferentially produced. All the structure assignments are based solely on mass spectral breakdown patterns, since pure compounds were not isolated.     

Fluorinated lignands in HPLC

Summary The chromatographic behaviour of C₆F₅(CH₂)₃SiCl₃, C₆H₅(CH₂)₃SiCl₃, CF₃(CF₂)₇CH₂CH₂SiCl₃ and n-C₁₀H₂₁SiCl₃ as well as the bonding of these ligands to silica is described. Phases with partially fluorinated ligands show entirely different chromatographic characteristics to analogous phases, where hydrogen replaces fluorine. The silica with the pentafluorophenyl-3-n-propyl-C₆F₅(CH₂)₃-ligand has higher k-values and a better selectivity for aromatic hydrocarbons than that with phenyl-3-n-propyl C₆H₅(CH₂)₃-groups, whereas the phase with the fluorinated carbon chain is less useful than the silica modified with n-decyltrichlorosilane n-C₁₀H₂₁SiCl₃. The first effect can be explained by complex formation, and the second may be due to a different contact area between the ligand and the solute. The normal hydrocarbon chains hinder each other sterically and expose many adsorption sites, in contrast the perfluorinated chains are sterically fixed and are the first example of real brushes in HPLC.     

Fluorinated phosphorus compounds: Part 6. The synthesis of bis(fluoroalkyl) phosphites and bis(fluoroalkyl) phosphorohalidates

Reaction of phosphorus trichloride with tert-butanol and fluoroalcohols gave bis(fluoroalkyl) phosphites (R_FO)₂P(O)H in 42-89% yield, where R_F=HCF₂CH₂, H(CF₂)₂CH₂, H(CF₂)₄CH₂, CF₃CH₂, C₂F₅CH₂, C₃F₇CH₂, (CF₃)₂CH, (FCH₂)₂CH, CF₃(CH₃)₂C, (CF₃)₂CH₃C, CF₃CH₂CH₂, C₄F₉CH₂CH₂ and C₆F₁₃CH₂CH₂. Treatment of these with chlorine in dichloromethane gave the bis(fluoroalkyl) phosphorochloridates (R_FO)₂P(O)Cl in 49-96% yield. The chloridate (CF₃CH₂O)₂P(O)Cl was isolated in much lower yield from the interaction of thionyl chloride with bis(trifluoroethyl) phosphite. Heating the latter in dichloromethane with potassium fluoride and a catalytic amount of trifluoroacetic acid gave the corresponding fluoridate (CF₃CH₂O)₂P(O)F in 84% yield. Treatment of bis(trifluoroethyl) phosphite with bromine or iodine gave the bromidate (CF₃CH₂O)₂P(O)Br and iodidate (CF₃CH₂O)₂P(O)I in 51 and 46% yield, respectively. The iodidate is the first dialkyl phosphoroiodidate to have been isolated and characterised properly—its discovery lags behind the first isolation of a dialkyl phosphorochloridate by over 130 years. The fluoroalkyl phosphoryl compounds are generally more stable than known unfluorinated counterparts.     

Ringöffnende acetylierung eines an kobalt koordinierten ringliganden vom divinylboran-typ

(C₅H₅)Co[2–6-η-(CH₃)₂Si(CHCH)₂BC₆H₅(III) is prepared photochemically from (C₅H₅)Co(CO)₂ and (CH₃)₂Si(CHCH)₂BC₆H₅ (II). Acetylation of the new complex III with CH₃COCl/AlCl₃ and subsequent hydrolysis effect ring-opening new complex III with CH₃COCl/AlCl₃ and subsequent hydrolysis effect ring-opening to give (C₅H₅)Co[(1,2-η-(cis-CH₃COCH)CH(η-CH₂CH)Si(CH₃)₂] (IV) which slowly isomerizes (ΔG^≠₂₉₆ 100 ± 2 kJ mol^?1) to the corresponding trans-isomer (V).Pure (CH₃)₂Si(CHCH)₂Sn(CH₃)₂ (I) can be obtained in preparative quantities via the new complex (CH₃)₂Si(CHCH)₂Sn(CH₃)₂ · 2 CuCl.     

The steric and electronic effects of aliphatic fluoroalkyl groups

Ab initio calculations were performed on 18 fluorinated and unfluorinated alcohols at the B3LYP and HF levels with the 6-311G^∗∗ basis set. Molar volumes of the alcohols were computed at each level and averaged to produce a scale of relative size. From this, various isosteric replacements of potential use in drug design were suggested: ethyl by FCH₂CH₂ or HCF₂CH₂, propyl by CF₃CH₂, isopropyl by CF₃(CH₃)CH or (FCH₂)₂CH, isobutyl or t-butyl by (CF₃)₂CH, and 3-methyl-2-butyl by CF₃(CH₃)₂C. Calculation of the charge on oxygen and the Wiberg index of the CO bond allowed an electronegativity scale to be constructed for the fluoroalkyl groups. Electronegativity decreased in the order: (CF₃)₃C>(CF₃)₂CH>C₂F₅CH₂>CF₃CH₂>CH₃(CF₃)₂C>HCF₂CH₂>CF₃(CH₃)CH>(FCH₂)₂CH>FCH₂CH₂>CF₃(CH₃)₂C. This ranking agreed with literature acid dissociation data for the alcohols studied.     

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.     

Mass spectrometric identification of multicage fullerene cycloadducts

Multicage fullerene cycloadducts have been detected by MALDI mass spectrometry; they have been found as admixtures in the products of reactions of the trifluoromethylation of fullerene samples doped with metallic sodium, the reaction between fullerenes and a mixture of trifluoromethylfullerenes, and the synthesis of fulleroproline esters. As a result, over 75 new compounds of this type have been identified. The optimization of the synthesis procedures and chromatographic fractionation allowed us to extract five compounds in the pure form: (C₆₀)₂(CF₂)₂(CF₃)₈, (C₆₀)₂(CF₂)₂(CF₃)₃C₂F₅, (C₆₀)₂(CF₂)₂(CF₃)₅C₂F₅, (C₆₀)₂(CF₂)₂(CF₃)₂O, and C₆₀CH₂N(CH₂C₆₀)CCOOtBu. Chemical structures of two of them, proposed on the basis of post source decay mass spectra, have been further confirmed by NMR spectra.     

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.     

Fluorinated tropylium ions in the mass spectra of some polyfluoroaromatic compounds

The most prominent ion in the mass spectra of C₆F₅CH₂X (X ? H, Br, CH:CH₂, COCl, and CH₂C₆F₅) is C₇F₅H₂⁺, formulated as the pentafluorotropylium cation. This ion is also found, in an amount comparable to the parent ion, in the spectrum of (C₆F₅)₂CH₂. The heptafluorotropylium cation is found similarly in the spectrum of C₆F₅CF₃. The mass spectra of (C₆F₅)₂CHBr and [(C₆H₅)₂CH]₂ exhibit an ion C₁₃F₁₀H⁺ as the base peak, which is probably a pentafluorophenylpentafluorotropylium cation. The alcohol (C₆F₅)₂CHOH shows loss of C₆F₅, followed by 2H, as a major breakdown pathway. The mode of formation, and the subsequent fragmentation, of the major ions in these spectra, are discussed.     

New types of asymmetrical bromonium salts [RF(RF′)Br]Y where RF and/or RF′ represent perfluorinated aryl, alkenyl, and alkynyl groups

A series of previously unknown asymmetrical fluorinated bis(aryl)bromonium, alkenyl(aryl)bromonium, and alkynyl(aryl)bromonium salts was prepared by reactions of C₆F₅BrF₂ or 4-CF₃C₆H₄BrF₂ with aryl group transfer reagents Ar′SiF₃ (Ar′ = C₆F₅, 4-FC₆H₄, C₆H₅) or perfluoroorganyl group transfer reagents R_F′BF₂ (R_F = C₆F₅, trans-CF₃CFCF, C₃F₇C≡C) preferentially in weakly coordinating solvents (CCl₃F, CCl₂FCClF₂, CH₂Cl₂, CF₃CH₂CHF₂ (PFP), CF₃CH₂CF₂CH₃ (PFB)). The presence of the base MeCN and the influence of the adducts R_F′BF₂·NCMe (R_F = C₆F₅, CF₃C≡C) on reactions aside to bromonium salt formation are discussed. Reactions of C₆F₅BrF₂ with Alk_F′BF₂ in PFP gave mainly C₆F₅Br and Alk_F′F (Alk_F′ = C₆F₁₃, C₆F₁₃CH₂CH₂), presumably, deriving from the unstable salts [C₆F₅(Alk_F′)Br]Y (Y = [Alk_F′BF₃]⁻). Prototypical reactivities of selected bromonium salts were investigated with the nucleophile I^-and the electrophile H⁺. [4-CF₃C₆H₄(C₆F₅)Br][BF₄] showed the conversion into 4-CF₃C₆H₄Br and C₆F₅I when reacted with [Bu₄N]I in MeCN. Perfluoroalkynylbromonium salts [C_nF_2n+1C≡C(R_F)Br][BF₄] slowly added HF when dissolved in aHF and formed [Z-C_nF_2n+1CFCH(R_F)Br][BF₄].     

Mono- and dihydryl-pentafluorosulfur-F-alkanes [1]

The systematic preparation of partially fluorinated pentafluorosulfur alkanes containing no additional halogens is reported. Thus, the indirect addition of “HF” (via KF/formamide) to SF₅CH=CF₂, SF₅CFCF₂, and SF₅C(CF₃)CF₂ produces SF₅CH(in2)CF₃, SF₅CHFCF₃, and SF₅C(CF₃)₂H respectively. The monohydryl-pentafluorosulfur-F- alkanes react readily with S₂O₆F₂ to form the corresponding fluorosulfates by oxidative displacement of hydrogen, while the dihydryl derivative undergoes cleavage to produce F-acetyl fluoride. Efforts to convert some of the new materials to the important but unknown pentafluorosulfur “ketone,” SF₅C(O)CF₃, were unsuccessful.     

High-yield catalytic metathesis of alkenyl tosylates with applications in organic synthesis

Alkenyl tosylates of the type RCHCH(CH₂)_nOTs [RH, n=9; RH, n=7; and RCH₃(CH₂)₇, n=8] undergo metathesis using a WCl₆-Me₃SnCl catalyst system, producing difunctionalised alkenes of the type TsO(CH₂)_nCHCH(CH₂)_nOTs (n=7,8, and 9); examples of the use of these products in synthesis are presented.     

Phenyl(acyloxy)fluorosilanes C6H5Si(OCOR)nF3?n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C6H5Si(OCOR)FCl

The method of synthesis of the hitherto unknown class of organosilicon compounds, phenyl(acyloxy)fluorosilanes C₆H₅Si(OCOR) _n F_3−n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C₆H₅Si(OCOR) FCl in up to 91% yield has been developed based on the reaction of phenyl(fluoro)chlorosilanes C₆H₅SiCl _n F_3−n (n = 1, 2) with trimethylsilyl esters of carboxylic acids Me₃SiOC(O)R [R = H, CH₃, CF₃, CCl₃, ClCH₂, BrCH₂, CH₂=CHCH₃, CH₂=CHPh, CH(CH₃)=CH₂, Ph].     

Systematische untersuchungen über das verhalten von organozinn-verbindungen gegenüber flüssigem schwefel-dioxid : V. Reaktionen von perfluorierten organozinn-derivaten Mit SO2

To get a clear conception of the mechanism of SO₂ insertion into tin-carbon bonds, reactions of perfluorinated organotin compounds with liquid SO₂ were studied in detail. Of the pure perfluoroorgano derivativs (C₆F₅)₄Sn is completely inert, while (CF₂CF)₄Sn shows a slight reactivity. In mixed tetraorganotin compounds like (C₆H₅)₃SnC₆F₅ and (C₆H₅)₃SnCFCF₂ insertion takes place only into the tinphenyl bond. The case of (CH₃)₃SnC₆F₅ is interesting in so far that the presence of the C₆F₅ group deactivates the whole molecule towards attack by SO₂. Possible reasons for this effect are discussed. We also report on the synthesis of triphenyltin perfluoromethanesulfinate, (C₆H₅)₃SnO₂-SCF₃.     

Binuclear ruthenium complexes of fluorous phosphine ligands: Synthesis, properties, and biphasic catalytic activity. Crystal structure of [Ru(μ-O2CMe)(CO)2P(CH2CH2(CF2)5CF3)3]2

The fluorocarbon soluble, binuclear ruthenium(I) complexes [Ru(μ-O₂CMe)(CO)₂L^F]₂, where L^F is the perfluoroalkyl substituted tertiary phosphine, P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃, or P(CH₂CH₂(CF₂)₅CF₃)₃, were synthesized and partition coefficients for the complexes in fluorocarbon/hydrocarbon biphases were determined. Catalytic hydrogenation of acetophenone to 1-phenylethanol in benzotrifluoride at 105 °C occured in the presence of either [Ru(μ-O₂CMe)(CO)₂P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃]₂ (1) or [Ru(μ-O₂CMe)(CO)₂P(CH₂CH₂(CF₂)₅CF₃)₃]₂ (2). The X-ray crystal structure of [Ru(μ-O₂CMe)(CO)₂P(CH₂CH₂(CF₂)₅CF₃)₃]₂ was determined. The compound exhibited discrete regions of fluorous and non-fluorous packing.     

Alkaline hydrolysis of diaryl ditellurides under phase transfer conditions; synthesis of alkyl aryl tellurides

The disproportionation reaction of diaryl ditellurides [(C₆H₅Te)₂, (p-CH₃C₆H₄Te)₂, (p-CH₃OC₆H₄Te)₂, (p-C₂H₅OC₄Te)₂, (2-naphthyl-Te)₂] with sodium hydroxide under phase transfer conditions at room temperature is described for the first time. The phase transfer catalyst used is 2HT-75, a trade name for a mixture of dialkyldimethylammonium chlorides. The intermediates aryl tellurolates react “in situ” with alkyl halides to give the corresponding alkyl aryl tellurides (ArTeR) in 52–72% yield. The following compounds were prepared: Ar  C₆H₅, R=CH₃(CH₂)₃CH₂, (CH₃)₂CHCH₂CH₂, (CH₃)₂CHCH₂, CH₃CHBrCH₂CH₂, CH₃(CH₂)₈CH₂, C₆H₅CH₂, ClCH₂, C₆H₅CH₂CH₂, CH₂CHCH₂, C₆H₅CHCHCH₂, C₆H₅SeCH₂, $\text{CH}{}_2\text{CH}{}_2\text{CH}{}_2\text{CHCHC}$H; Ar=p-CH₃C₆H₄, R = CH₃(CH₂)₂CH₂; Ar=p-CH₃OC₆H₄, R = CH₃(CH₂)₂CH₂; Ar = p-CH₂H₅OC₆H₄, R= CH₃(CH₂)₂CH₂; Ar = 2-naphthyl, R = CH₃(CH42)₂CH₂.     

Allylstannation: II. A total “cis-preference” in the addition of n-Bu2ClSnCH(CH3)CHCH2 to aldehydes

1-Buten-3-yldi-n-butylchlorotin, formed by redistribution of ($\text{E}\text{Z}$)-2-butenyltri-n-butyltin and Bu₂SnCl₂, reacts readily with neat RCHO (R  C₂H₅, C₂H₅(CH₃)CH, (CH₃)₂CH, (CH₃)₃C and C₆H₅) to give high yields (80–100%) of alcohols of the type RCH(OH)CH₂CHCHCH₃ only in the Z-configuration. This appears to be the first example of total “cis-preference” in the addition of Grignard-like reagents to carbonyl compounds. The results are discussed in terms of steric requirements around the tin centre which is probably five-coordinate in the transition state.     

Reactivity of olefin an acetylene complexes of platinum(0) towards tetrachloro-o-benzoquinone

Tetracloro-o-benzoquinone reacts with (diphenylacetylene)bis(tirphenylphosphine)platinum(0) to give the novel platinum(II) diphenylacetylene complex, Pt(C₆Cl₄O₂)PhCCPh)(PPh₃), (I), which reacts with hydrogen halides to give the compelexes cis-PtX₂(PhCCPh((PPh₃), (X = Cl or Br). Hydrogen chloride also readily removes the tetrachloro-o-benzoquinoneligand from the adducts Ni(C₆Cl₄O₂)(Ph₂PCH₂CH₂PPh₂) and M(C₆Cl₄O₂)(PPh₃)₂, (M = Pd or Pt) but it has no reaction upon Ir(Cl)(C₆Cl₄O₂)(CO)(PPh₃)₂ at room temperature. The acetylene in (1) is susceptible to nucleophilic attact and reaction with diethylamine gives the vinyl adduct Pt(C₆Cl₄O₂)(CPhCPh)NHEt₂)(PPh₃). Other reactions of (I) have also been studied. Attemps to prepare other olefin or acetylene complexes of platinum(II) by the action of tetrachlor-o-benzoquinone on the complexes Pt(L)(PPh₃)₂, (L = PhCCH,(Et)(Me)(HO)CCCC(OH)(Me)(Et), HOCH₂OH, CF₃CCCF₃, CF₂CF₂, CF₂CH₂ or trans-PhCHCHPh) are also described.     

Fluoroborates by Cleavage of Trimethylamine‐bis(trifluoromethyl)boranes with NEt3 × 3 HF. Structures of C6F5(CF3)2B · NMe3, K[C6H5CH2(CF3)2BF], and K[C6H5(CF3)2BF]

Trimethylamine‐bis(trifluoromethyl)boranes R(CF₃)₂B · NMe₃ (R = cis/trans‐CF₃CF=CF ( 1/2 ), HC≡C ( 3 ), H₂C=CH ( 4 ), C₂H₅ ( 5 ), C₆H₅CH₂ ( 6 ), C₆F₅ ( 7 ), C₆H₅ ( 8 )) react with NEt₃ × 3 HF depending on the nature of R at 155–200 °C under replacement of the trimethylamine ligand to form the corresponding fluoro‐bis(trifluoromethyl)borates [R(CF₃)₂BF]^– ( 1 a/2 a – 8 a ). The structures of 7 , K[C₆H₅CH₂(CF₃)₂BF] ( K‐6 a ), and K[C₆H₅(CF₃)₂BF] ( K‐8 a ) have been investigated by single‐crystal X‐ray diffraction. In 7 the CF₃ groups make short repulsive contacts with NMe₃ and C₆F₅ entities – the B–CF₃ bonds being unusually long. The B–F bond lengths of K‐6 a and K‐8 a (1.446(3) and 1.452(2) Å, respectively) are long for a fluoroborate.     

Fluorinated phosphorus compounds: Part 8. The reactions of bis(fluoroalkyl) phosphorochloridates with sulfur nucleophiles

The reactivity of bis(fluoroalkyl) phosphorochloridates to nucleophiles is summarised. Previous data and the results described here indicate that reactivities decrease in the order: amines>alcohols>thiols. The synthesis of CF₃CH₂OP(O)(SEt)₂ in 30% yield was accomplished by treating CF₃CH₂OP(O)Cl₂ with two molar equivalents of EtSH and Et₃N in ether. The chloridates (CF₃CH₂O)₂P(O)Cl and (C₂F₅CH₂O)₂P(O)Cl did not react with MeSH in ether at −78 °C or when heated with Pb(SMe)₂ in benzene. Ethanethiol and propanethiol reacted with fluorinated chloridates in the presence of triethylamine to give thiolates (R_FO)₂P(O)SR in 13-41% yield where R_F was CF₃CH₂, C₂F₅CH₂, C₃F₇CH₂ or (CF₃)₂CH and R was Et or n-Pr. Similarly, reaction of phosphorobromidates (R_FCH₂O)₂P(O)Br, made by brominating the corresponding bis(fluoroalkyl) H-phosphonates, with benzenethiol gave derivatives (R_FCH₂O)₂P(O)SPh in 43 and 46% yield where R_F was CF₃ and C₂F₅, respectively. Treatment of the chloridothiolate Cl(EtO)P(O)SMe, prepared in two steps from triethyl phosphite, with fluoroalcohols and triethylamine in ether gave species R_FO(EtO)P(O)SMe in 62-74% yield where R_F was CF₃CH₂, C₂F₅CH₂, C₃F₇CH₂ or (CF₃)₂CH. The reactions of bis(trifluoroethyl) phosphorochloridate with 2-mercaptoethanol, 3-mercaptopropanol and ethane-1,2-dithiol gave several unexpected products whose structures were tentatively assigned.