Novel generation ponytails in fluorous chemistry: Syntheses of primary, secondary, and tertiary (nonafluoro-tert-butyloxy)ethyl amines

(Nonafluoro-tert-butyloxy)ethyl tosylate 4 was prepared in 65% yield from nonafluoro-tert-butanol 1 using commercially available reagents. Further reaction of 4 with HNR¹R² (R¹ = R² = H, CH₃; R¹ = H, R² = CH₃, (CH₂)₃C₈F₁₇, CH₂CH₂OC(CF₃)₃) affords the appropriate (CF₃)₃COCH₂CH₂NR¹R² amines in 20-69% yields. Improved overall yields of [(CF₃)₃COCH₂CH₂]_3−nNR_n to 1 were obtained by the reaction of (CF₃)₃CONa 2 and (XCH₂CH₂)_3−nNR_n (X = Cl, n = 0, 1, 2, R = CH₃; X = CH₃SO₂O, n = 1, R = CH₃SO₂) nitrogen mustards and a similar reactive β-substituted ethyl amine. The title amines are mobile colorless liquids and volatile with steam. The bulky fluorous ponytail (CF₃)₃CO(CH₂)₂ displays high acidic stability and increases fluorous character almost as much as the classical straight-chain C₈F₁₇(CH₂)₃ ponytail.     

Synthesis of ethyl zinc fluoroalkoxide complexes and the crystal structure of [EtZn(py){μ-OCH(CF3)2}]2

Fluorinated alkoxide complexes of zinc were synthesized for possible use as precursors to fluorine-doped ZnO films. Diethyl zinc reacted with fluorinated alcohols to form [EtZn(OR_f)]_n (R_f = CH(CF₃)₂, CMe₂CF₃, CMe(CF₃)₂) compounds. The [EtZn(OR_f)]_n compounds reacted with excess pyridine to yield the pyridine adducts [EtZn(py)(μ-OR_f)]₂. The X-ray structure of [EtZn(py){μ-OCH(CF₃)₂}]₂ showed that it has virtual C_i symmetry.     

Synthesis and properties of gemini-type hydrocarbon-fluorocarbon hybrid surfactants

Gemini-type hybrid surfactants with two fluorocarbon chains connected through a hydrocarbon spacer, F(CF₂)_m(CH₂)₂CH(OSO₃Na)(CH₂)_nCH(OSO₃Na)(CH₂)₂(CF₂)_mF [Fm(Hn)FmOS, m = 4, 6; n = 5, 6, 7, 8)], were synthesized and their surface chemical properties were examined with the aim to have highly functional and highly water-soluble fluorinated surfactants when compared with the conventional fluorinated surfactants. Comparisons of the surface chemical properties of the synthesized gemini-type hybrid surfactants with those of monounit-type hybrid surfactants, F(CF₂)_m(CH₂)₂CH(OSO₃Na)(CH₂)_nH [FmEHnOS, m = 4, 6; n = 3, 5)], revealed that gemination causes a remarkable lowering (about 1/100) in cmc value while it produces little changes in Krafft point (below 0 °C) and surface tension at cmc (γ_cmc).     

Synthesis and characterization of partially fluorinated ethers

A series of partially fluorinated ethers PFE-m,n with general formula F(CF₂)_mCH₂CH₂O(CH₂)_nH (m = 4, 6, 8 and n = 2, 3, 5, 8, 14, 18, 21) has been synthesized and characterized. The present work aimed to investigate the synthesis of PFE-m,n and evaluate some of their fundamental physico-chemical properties such as: specific gravity, refractive index, viscosity, solid-solid transitions, solubility and amphiphile surface activity in a variety of solvents. Further, a comparison between PFE-m,n and the well known semifluorinated n-alkanes F(CF₂)_m-(CH₂)nH (FHm, n) with the same value of the m/n ratio have been reported.     

Synthesis and coordination chemistry of fluorinated xanthate ligands

Alkali metal, copper, nickel and rhodium complexes of alkylated [S₂COC₈H₁₇] and fluoroalkylated xanthate ligands [S₂COC_mH_2mC_nF_2n+1] (m = 2, n = 4, 6; m = 3, n = 1, 8) have been prepared in high yields and characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Cu(S₂COC₈H₁₇)(PPh₃)₂], [Cu(S₂COC₃H₆CF₃)(PPh₃)₂], [Ni(S₂COC₃H₆CF₃)₂], [Cp^*RhCl(S₂COC₈H₁₇)] and [Cp^*RhCl(S₂COC₃H₆CF₃)] have been determined by single crystal X-ray diffraction.     

First examples of stable polyfluorinated bis- and tris-(alkoxy)methyl cations

Stable polyfluorinated bis- and tris-(alkoxy)methyl cations were prepared by the reaction of the corresponding difluoroformals (R_fO)₂CF₂ (R_f = -CH₂CF₃, -CH(CF₃)₂, -CH₂CF₂Cl) with an excess of SbF₅. Although the cation (CF₃CH₂O)₂CF⁺ (1a) is stable at ambient temperature, the chlorinated analog (ClCF₂CH₂O)₂CF⁺ (3a) can be generated only at low temperature in SO₂ClF solvent and rapidly decomposes at ambient temperature. Although the salt [(CF₃)₂CHO]₂CF⁺Sb_nF_5n+1⁻ (2a) is slightly more stable than the salt of cation 3a, at ambient temperature it undergoes rapid disproportionation with formation of equal amounts of [(CF₃)₂CHO]₃C⁺Sb_nF_5n+1⁻ (2b) and CF₃OCH(CF₃)₂ (2c). Stable solid salt 2b (n = 2) was isolated and fully characterized by ¹H, ¹⁹F and ¹³C NMR spectroscopy and its structure was confirmed by single crystal X-ray diffraction.     

Syntheses of fluorous quaternary ammonium salts and their application as phase transfer catalysts for halide substitution reactions in extremely nonpolar fluorous solvents

Perfluoromethyldecalin solutions of the fluorous alkyl halides R_f8(CH₂)_mX (m=2, 3; X=Cl, I) are inert toward aqueous NaCl, KI, KCN, and NaOAc. However, substitution occurs at 100 °C in the presence of 10 mol % of the fluorous ammonium salts (R_f8(CH₂)₂)(R_f8(CH₂)₅)₃N⁺ I⁻ (1) or (R_f8(CH₂)₃)₄N⁺ Br⁻ (2) (10 mol %), which are fully or partially soluble in perfluoromethyldecalin under these conditions. Stoichiometric reactions of (a) 1 and R_f8(CH₂)₃Br, and (b) 2 and R_f8(CH₂)₂I are conducted in perfluoromethyldecalin at 100 °C, and yield the same R_f8(CH₂)_mI/R_f8(CH₂)_mBr equilibrium ratio (60-65:40-35). This shows that ionic displacements can take place in extremely nonpolar fluorous phases, and suggests a classical phase transfer mechanism for the catalyzed reactions. Interestingly, the non-fluorous ammonium salt mixture CH₃(CH₃(CH₂)_m)₃N⁺ Cl⁻ (3, Aliquat^® 336; m=2:1 7/9) also catalyzes halide substitutions, but under triphasic conditions with 3 suspended between the lower fluorous and upper aqueous layers. NMR experiments establish very low solubilities in both phases, suggesting interfacial catalysis.     

Synthesis and characterization of tri-block fluorinated-n-alkanes

A series of triblock semifluorinated n-alkanes of general formula F(CF₂)_n(CH₂)_m(CF₂)_nF (n = 6, 8 and m = 4, 6, 8) have been synthesized and characterized. The synthesis of triblock compounds was performed in two different ways according to the length of the hydrogenated moiety. Coupling of two molecules of β-(perfluoro-n-alkyl)ethyl iodides leads to the triblock materials F(CF₂)₆(CH₂)₄(CF₂)₆F and F(CF₂)₈(CH₂)₄(CF₂)₈F. The synthesis of compounds with larger hydrogenated part is accomplished in two steps by the addition of perfluoro-n-alkyl iodide F(CF₂)_nI to 1,5-hexadiene and 1,7-octadiene, respectively to give the diiodo-adducts which are subsequently deiodinated to the final triblock products F(CF₂)₆(CH₂)₆(CF₂)₆F, F(CF₂)₆(CH₂)₈(CF₂)₆F, F(CF₂)₈(CH₂)₆(CF₂)₈F and F(CF₂)₈(CH₂)₈(CF₂)₈F. The obtained triblock semifluorinated n-alkanes are characterized by low surface free energies with good lubricant properties usable as additives in ski-wax formulations.     

Synthesis and characterization of fluorous (S)- and (R)-1-phenylethylamines that effect heat facilitated resolution of (±)-2-(8-carboxy-1-naphthylsulfinyl)benzoic acid via diastereomeric salt formation and study of their circular dichroism

Perfluoroalkyl- or nonafluoro-tert-butoxy-alkyl-substituted enantiopure amines having the structure PhCHCH₃(NR¹R²) [R¹ = H, CH₃; R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃; R¹ = R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃] are obtained in high yields, when (S)-(−)-1-phenylethylamine is reacted with readily accessible alkylating reagents or fluorous 2° amines (R¹ = H; R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃) are methylated in a Leuckart-Wallach reaction. The solubility patterns of these novel chiral amines and their hydrochlorides are qualitatively described for a broad spectrum of solvents and the fluorous partition coefficients of the free bases are determined by GC. A novel method for the resolution of enantiomers is disclosed here, which involves the use a half-equivalent of the selected resolving agent in solvent water that displays low solubility for the crystalline diastereomeric salt(s) formed even at temperatures near to its boiling point. Compound (S)-(−)-PhCHCH₃[NH(CH₂)₃C₈F₁₇] is found to satisfy all the latter conditions and successfully used for the heat facilitated resolution of the title racemic acid. The circular dichroism (CD) spectra of six novel fluorous (S)-(−)-1-phenylethylamine derivatives are measured in ethanol, trifluoroethanol and hexafluoropropan-2-ol and discussed in detail.     

Synthesis and repellent properties of vinylidene fluoride-containing polyacrylates

Fluorinated polyacrylats with side group containing vinylidene fluoride (VDF) units (CF₃(CF₂)_n (CH₂CF₂)_m, n = 3, 5; m = 1, 2) were successfully synthesized. The water and oil repellency properties of these polymers are similar to those of fluorinated polyacrylate with side group containing long perfluorooctyl group (CF₃(CF₂)₇). The thermal telomerization of CF₃(CF₂)₅I and CF₃(CF₂)₃I with vinylidene fluoride (VDF) provided CF₃(CF₂)₅CH₂CF₂I (1b) and CF₃(CF₂)₃CH₂CF₂CH₂CF₂I (1c), respectively. The addition of 1b with ethylene followed by hydrolysis gave CF₃(CF₂)₅CH₂CF₂CH₂CH₂OH (2b). Treatment of 1c with ethyl vinyl ether in the presence of Na₂S₂O₄ followed by reduction produced CF₃(CF₂)₃CH₂CF₂CH₂CF₂CH₂CH₂OH (2c). Fluoroacrylates 3b-d were prepared by acrylation of the corresponding fluoroalcohols 2b-d. The semi-continuous process emulsion co-polymerization of 3a-d with octadecyl acrylate and 2-hydroxylethyl acrylate initiated by (NH₄)₂S₂O₈ in the presence of a mixture emulsifiers of polyoxyethylene(10)nonyl phenyl ether (TX-10) and sodium lauryl sulfate provided stable latexes 4a-d, respectively. The water and oil repellency properties of 4b (R_f: CF₃(CF₂)₅CH₂CF₂) and 4c (R_f: CF₃(CF₂)₃CH₂CF₂CH₂CF₂) containing vinylidene fluoride (VDF) units were similar to those of 4a (R_f: CF₃(CF₂)₇) containing long perfluoroalkyl group and much better than those of polymer 4d (R_f: CF₃(CF₂)₃) with short perfluoroalkyl chain. Thus, polyacrylates containing vinylidene fluoride units showed promising aspects as the alternatives to the currently used water and oil repellent agents with long perfluoroalkyl chains.     

Synthesis,properties, and reactions of enantiomerically pure,chiral fluorous phosphines of the formula (menthyl)P(CH2CH2(CF2)n−1CF3)2 (n=6, 8)

Reactions of (menthyl)PH₂ and H₂CCHR_f6 (menthyl=1R,3R,4S; R_fn=(CF₂)_n−1CF₃) or H₂CCHR_f8 (AIBN, refluxing THF) give (menthyl)PH(CH₂CH₂R_fn) and then (menthyl)P(CH₂CH₂R_fn)₂ (n=6, 7; n=8, 8), but with purification or other difficulties at each stage. Reactions of (menthyl)PCl₂ with IMgCH₂CH₂R_fn give, under careful conditions, analytically pure 7 or 8 in 28–32% yields after distillation. Some R_fn(CH₂)₄R_fn also form. These represent the first chiral (and non-racemic) fluorous phosphines. Reactions of 7 or 8 with [Ir(COD)Cl]₂ and CO give trans-[(menthyl)P(CH₂CH₂R_fn)₂]₂Ir(Cl)(CO) (n=6, 71%; 8, 51%) as analytically pure yellow oils. Their IR ν_CO values show the donor/acceptor properties of 7 and 8 to be intermediate between those of P((CH₂)₃R_f8)₃ and P((CH₂)₄R_f8)₃. The CF₃C₆F₁₁:toluene partition coefficients of 7 and 8 (27°C, 78.4:21.6 and 93.7:6.3) are distinctly lower than those of P((CH₂)₂R_fn)₃ (n=6, 98.8:1.2; n=8, >99.7:<0.3), reflecting the replacement of a linear C₈–C₁₀ group that is ca. 75–80% fluorinated by a cyclic C₁₀ terpenyl group. Reactions of 7 or 8 with [Rh(COD)Cl]₂ give [(menthyl)P(CH₂CH₂R_fn)₂]Rh(Cl)(COD) (n=6, 69%; 8, 70%) as orange crystallizable oils.     

Synthesis of novel lipophilic and/or fluorophilic ethers of perfluoro-tert-butyl alcohol, perfluoropinacol and hexafluoroacetone hydrate via a Mitsunobu reaction: Typical cases of ideal product separation

Fluorophilic ethers having the structure RC(CF₃)₂O(CH₂)₃C_nF_2n + 1 are obtained in high yields, when F-tert-butyl alcohol (R = CF₃), F-acetone hydrate (R = O(CH₂)₃C_nF_2n + 1), F-pinacol (R = C(CF₃)₂O(CH₂)₃C_nF_2n + 1) are reacted with 3-perfluoroalkyl-1-propanols (C_nF_2n + 1(CH₂)₃OH, n = 4, 6, 8, 10) in a Mitsunobu reaction (Ph₃P/DIAD [i-PrO₂CN = NCO₂Pr-i]/ether). The parent lipophilic ethers with the structure of (CF₃)₃CO(CH₂)₃C_nH_2n + 1 were prepared analogously using the corresponding fatty alcohols and F-tert-butyl alcohol. To achieve ideal separations, products were transferred to orthogonal phases relative to the other reaction components using fluorous extraction, fluorous solid-organic liquid filtration, or steam-distillation. Selected physical properties including melting and boiling point, together with fluorous partition coefficients of these ethers were determined and the figures obtained were qualitatively analyzed using relevant thermodynamic theories. Some of these ethers are liquids with rather low freezing points and are miscible with fluorocarbon solvents.     

sp C-H bond functionalization of methyl n-alkyl ketones [MeCOCnH2n+1 (n = 6-8)] as a novel method for the one-pot regioselective synthesis of ‘bifunctional alkanes’ with remote functional groups

Selective one-pot functionalization of methyl n-alkyl ketones, C_nH_2n+1COMe (n = 6-8) involving C-sp³-H bond cleavage with CO and various nucleophilic substrates [ⁱPrOH, BuCH(Et)CH₂OH, CF₃CH₂OH, (CF₃)(Me)CHOH, H(CF₂)₂CH₂OH, HCCCH₂OH, furan, thiophene, and anisole] in the presence of the superelectrophilic system CBr₄·2AlBr₃ has been performed for the first time.     

From hypervalent xenon difluoride and aryliodine(III) difluorides to onium salts: Scope and limitation of acidic fluoroorganic reagents in the synthesis of fluoroorgano xenon(II) and iodine(III) onium salts

Fluorinated organodifluoroboranes R_fBF₂ are in general suitable reagents to transform XeF₂ and RIF₂ into the corresponding onium tetrafluoroborate salts [R_fXe][BF₄] and [R(R_f)I][BF₄], respectively. (4-C₅F₄N)BF₂ and trans-CF₃CFCFBF₂ which represent boranes of high acidity form no Xe-C onium salts in reactions with XeF₂ but give the desired iodonium salts with RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄). The reaction of (4-C₅F₄N)BF₂ with XeF₂ ends with a XeF₂-borane adduct. C₆F₅Xe(4-C₅F₄N), the first Xe-(4-C₅F₄N) compound, was obtained when C₆F₅XeF was reacted with Cd(4-C₅F₄N)₂. We describe the synthesis of (4-C₅F₄N)IF₂ and reactions of (4-C₅F₄N)IF₂ and C₆F₅IF₂ with (4-C₅F₄N)BF₂. Analogous to [(4-C₅F₄N)₂I][BF₄] and [C₆F₅(4-C₅F₄N)I][BF₄] aryl(perfluoroalkenyl)iodonium salts [R(R′)I][BF₄] were obtained from RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄) and R′BF₂ (R′ = trans-CF₃CFCF, CF₂CF). The gas phase fluoride affinities pF⁻ of selected fluoroorganodifluoroboranes R_fBF₂ and their hydrocarbon analogs are calculated (B3LYP/6-31+G^*) and discussed with respect to their potential to introduce R_f-groups into hypervalent EF₂ bonds. Four aspects which influence the transformation of hypervalent EF₂ bonds (E = Xe, R′I) under the action of Lewis acidic reagents RAF_n−1 (A = B, P; n = 3, 5) into the corresponding [RE][AF_n+1] salts are presented and the important role of the acidity is emphasized. Fluoride affinities may help to plan the introduction of organo groups into EF₂ moieties and to expand the types of acidic reagents. Thus C₆H₅PF₄ with a pF⁻ value comparable to that of R_fBF₂ compounds is able to introduce the C₆H₅ group into RIF₂ (R = C₆F₅, p-C₆FH₄).     

High-temperature and photochemical syntheses of C60 and C70 fullerene derivatives with linear perfluoroalkyl chains

New experimental results on perfluoroalkylation of C₆₀ and C₇₀ with the use of R_fI (R_f = CF₃, C₂F₅, n-C₃F₇, n-C₄F₉, and n-C₆F₁₃), along with a critical overview of the existing synthetic methods, are presented. For the selected new fullerene (R_f)_n compounds we report spectroscopic, electrochemical and structural data, including improved crystallographic data for the isomers of C₇₀(C₂F₅)₁₀ and C₆₀(C₂F₅)₁₀, and the first X-ray structural data for the dodecasubstituted perfluoethylated C₇₀ fullerene, C₇₀(C₂F₅)₁₂, which possesses unprecedented addition pattern.     

Synthesis and properties of fluorous arenes and triaryl phosphorus compounds with branched fluoroalkyl moieties (“split pony tails”)

Most compounds designed for immobilization in fluorous media feature linear pony tails of the formula (CH₂)_m(CF₂)_n−1CF₃ [(CH₂)_mR_fn]. This paper presents a first-generation approach to compounds with branched or “split” pony tails of the formula (CH₂)_lCH[(CH₂)_mR_fn]₂. Allyl tri(n-butyl)tin is reacted twice with perfluorooctyl iodide (R_f8I; first, photochemical, 78-81%; second, thermal with radical initiator, 71%; 13-18 g scales) to give the secondary alkyl iodide ICH(CH₂R_f8)₂ (3). A subsequent Ni(Cl)₂(PPh₃)₂-catalyzed reaction with allyl tri(n-butyl)tin yields the branched alkene H₂CCHCH₂CH(CH₂R_f8)₂ (74%). A palladium-catalyzed Heck coupling with OP(p-C₆H₄Br)₃ gives the fluorous phosphine oxide OP(p-C₆H₄CHCHCH₂CH(CH₂R_f8)₂)₃ (84%), and Pd/C-catalyzed hydrogenation affords OP(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (>99%). Reduction with SiHCl₃ gives P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃, which is protected as the air-stable borane adduct H₃B·P(p-C₆H₄(CH₂)₃CH(CH₂R_f8)₂)₃ (9, 64%). The CF₃C₆F₁₁/toluene partition coefficient of 9 is much higher than that of the analog with p-(CH₂)₃R_f8 groups (96.6:3.4 versus 37.3:62.7). The iodide 3 is unreactive towards PAr₃ at 175-250 °C. However, a CuBr-catalyzed reaction with C₆H₅MgBr gives C₆H₅CH(CH₂R_f8)₂, which also exhibits a high partition coefficient (97.9:2.1).     

Fluorinated phosphorus compounds: Part 11. The reactions of some fluorinated amines with dialkyl and bis(fluoroalkyl) phosphorochloridates

Dimethyl phosphorochloridate reacted with R_FCH₂NH₂ in ether in the presence of Et₃N to afford (MeO)₂P(O)NHCH₂R_F, where R_F = CF₃ and C₂F₅, in 39 and 47% yield, respectively. Similar reactions with di-n-propyl and diisopropyl phosphorochloridates could be effected only with H₂NCH₂CF₃ when 4-dimethylaminopyridine catalyst was added and (n-PrO)₂P(O)NHCH₂CF₃ and (i-PrO)₂P(O)NHCH₂CF₃ were isolated in 49 and 25% yield, respectively. Treatment of POCl₃ with one molar equivalent each of H₂NCH₂CF₃ and Et₃N permitted the synthesis of Cl₂P(O)NHCH₂CF₃ in 43% yield. Bis(fluoroalkyl) phosphorochloridates (R_FO)₂P(O)Cl, where R_F = C₂F₅CH₂, C₃F₇CH₂ and (CF₃)₂CH, reacted with 2,2,2-trifluoroethylamine and 2,2,3,3,3-pentafluoropropylamine to furnish phosphoramidates (R_FO)₂P(O)NHCH₂R, where R = CF₃ or C₂F₅, in yields of 32-67%.     

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.     

Carbosiloxandendrimere mit terminalen SiH-Bindungen

An efficient method for the preparation of carbosiloxane dendrimers with end-grafted SiH-bonds is given by using the alcohols HOCH(Me)(CH₂)₄SiMe_3 − nH_n (4a: n = 1, 4b: n = 2, 4c: n = 3), which themselves are accessible by the hydrosilylation of MeCOCH₂CH₂CHCH₂ (1) with the chlorosilanes HSiMe_3 − nCl_n (2a: n = 1, 2b: n = 2, 2c: n = 3) and hydrogenation of the latter species with Li[AlH₄]. Alcohols 4a-4c can be used as starting materials for the preparation of carbosiloxane dendrimers of the 1^st-3^rd generation. For the synthesis of the 1^st generation dendrimers, Me_4 − mSiCl_m (5a: m = 1, 5b: m = 2, 5c: m = 3, 5d: m = 4) is reacted with 4a-4c in presence of NEt₃ as base. The dendritic molecules Me_4 − mSi[OCH(Me)(CH₂)₄SiMe_3 − nH_n]_m (n = 1: 6a, m = 1; 6b, m = 2; 6c, m = 3; 6d, m = 4. n = 2: 7a, m = 1; 7b,m = 2; 7c, m = 3; 7d, m = 4. n = 3: 8a, m = 3; 8b, m = 4) are thereby obtained in excellent yield. Carbosiloxane dendrimers of the 2^nd and 3^rd generation with a MeSiO₃- or SiO₄-core can be isolated from the reaction of MeSi(OCH₂CH₂CH₂SiMe₂Cl)₃ (9), MeSi(OCH₂CH₂CH₂SiMeCl₂)₃ (11), Si(OCH₂CH₂CH₂SiMe₂Cl)₄ (13) and MeSi(OCH₂CH₂CH₂SiMe(OCH₂CH₂CH₂SiMe₂Cl)₂)₃ (15) with 4a or 4b, respectively, under similar reaction conditions. Thereby MeSi[OCH₂CH₂CH₂SiMe₂OCH(Me)(CH₂)₄SiMe₂H]₃ (10), MeSi[OCH₂CH₂CH₂SiMe[OCH(Me)(CH₂)₄SiMe_3 − nH_n]₂]₃ (12a, n = 1; 12b, n = 2), Si[OCH₂CH₂CH₂SiMe[OCH(Me)(CH₂)₄SiMe₂H]₂]₄ (14) and MeSi[OCH₂CH₂CH₂SiMe[OCH₂CH₂CH₂SiMe₂OCH(Me)(CH₂)₄SiMe_3 − nH_n]₂]₃ (16) are formed as colourless oils.Compounds 3, 4, 6-8, 10, 12, 14 and 16 were characterised by elemental analysis as well as spectroscopic (IR, NMR) and mass spectrometric (ESI-TOF) studies.     

Fluorinated phosphorus compounds: Part 9. The reactions of bis(fluoroalkyl) phosphorochloridates with oxygen nucleophiles

Twenty nine bis(fluoroalkyl) phosphates (R_FO)₂P(O)OR were prepared in 18-75% yield by treating phosphorochloridates (R_FO)₂P(O)Cl, where R_F was HCF₂CH₂, HCF₂CF₂CH₂, H(CF₂)₄CH₂, C₂F₅CH₂, C₃F₇CH₂, (CF₃)₂CH, (FCH₂)₂CH and (CH₃)₂CF₃C with methanol, ethanol, propanol and isopropanol in diethyl ether in the presence of triethylamine. The bulky chloridate [(CH₃)₂CF₃CO]₂P(O)Cl reacted with methanol, ethanol and propanol, but not with isopropanol - even on heating in the presence of the catalyst 4-dimethylaminopyridine - due to steric hindrance at phosphorus. The relative reactivities of three of the chloridates decreased in the order [(CF₃)₂CHO]₂P(O)Cl > [(FCH₂)₂CHO]₂P(O)Cl > [(CH₃)₂CF₃CO]₂P(O)Cl. Also described is the synthesis of phosphates (CF₃CH₂O)₂P(O)OCH₂R, where R = CH₂Br, CH₂Cl, CH₂F and CHF₂, and diphosphates [H(CF₂)_nCH₂O]₂P(O)OCH₂(CF₂)₂CH₂OP(O)[OCH₂(CF₂)_nH]₂, where n = 1, 2 and 4.