- Copper-Mediated Fluorination of Aryl Trisiloxanes with Nucleophilic Fluoride
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A method for the nucleophilic fluorination of heptamethyl aryl trisiloxanes to form fluoroarenes is reported. The reaction proceeds in the presence of Cu(OTf)2 and KHF2 as the fluoride source under mild conditions for a broad range of heptamethyltrisiloxyarenes with high functional group tolerance. The combination of this method with the silylation of aryl C?H bonds enables the regioselective fluorination of non-activated arenes controlled by steric effects following a two-step protocol.
- Dorel, Ruth,Boehm, Philip,Schwinger, Daniel P.,Hartwig, John F.
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supporting information
p. 1759 - 1762
(2020/02/05)
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- Anhydrous flouride salts and reagents and methods for their production
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Anhydrous organic fluoride salts and reagents prepared by a method comprising the nucleophilic substitution of a fluorinated aromatic or fluorinated unsaturated organic compound with a salt having the formula: [QnM]x+Ax?in an inert polar, aprotic solvent; wherein M is an atom capable of supporting a formal positive charge, the n groups Q are independently varied organic moieties, n is an integer such that the [QnM] carries at least one formal positive charge, x is an integer defining the number of formal positive charge(s), +, carried by the [QnM], A? is an anionic nucleophile capable of substituting for F in the fluorinated compound and F represents fluorine or a radioisotope thereof.
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Page/Page column 5-6
(2008/06/13)
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- Anhydrous tetrabutylammonium fluoride
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Tetrabutylammonium fluoride (TBAF) is prepared at low temperature by nucleophilic aromatic substitution of hexafluorobenzene with tetrabutylammonium cyanide. Adventitious water is scavenged during this synthesis by the generated hexacyanobenzene, which readily adds water under basic conditions. Contrary to expectations, TBAF is stable to Hofmann elimination in polar aprotic solvents under anhydrous conditions. Added hydroxylic solvents are shown to catalyze the decomposition of TBAF and to catalyze proton exchange with DMSO. The synthetic utility of this salt is described briefly. Copyright
- Sun, Haoran,DiMagno, Stephen G.
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p. 2050 - 2051
(2007/10/03)
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- Synthesis of molybdenum and tungsten complexes that contain triamidoamine ligands of the type (C6F5NCH2CH2)3N and activation of dinitrogen by molybdenum
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Three new ligands of the type (ArNHCH2CH2)3N(Ar = 3,5-bis(trifluoromethyl)phenl,2-(trifluomethyl)-phenyl, and pentafluorophenyl) have been prepared. Only Mo and W complexes containing the [(C6F5NCH2CH2)3N] 3- ([N3N]3-) ligand were found to be stable. Stable complexes that have been prepared include Mo[N3N](NMe2), M[N3N]Cl (M = Mo or W), Mo[N3N](OTf) (M = Mo or W), [N3N]M≡N (M = Mo or W), and {[N3N]Mo=NMe}-(Otf). An X-ray study of Mo[N3N]Cl showed it to be a monomeric distorted trigonal bipyramidal species having a pseudo-C3 symmetry (space group P1, a = 11.265(2) ?, b = 11.371(2) ?, c = 21.805(4) ?, α = 82.40(1)°, β = 79.07(1)°, γ = 74.89(1)°, V = 2637.4 ?3, Z = 4, fw = 772.75, ρ(calcd) = 1.946 g/cm3, R = 0.032, Rw = 0.034). Reduction of Mo[N3N](OTf) with 1 equiv of sodium amalgam yields a dinuclear bridging dinitrogen species, [N3N]-Mo(μ-N2)Mo[N3N]. In the presence of 2 equiv of sodium amalgam in ether Mo[N3N](Otf) is reduced to [N3N]-Mo(N2) [Na(ether)x] (1 3N]Mo(μ-N2)Mo[N3N] can be reduced to [N3N]Mo(N2)[NaLx] by sodium amalgam under dinitrogen and the latter can be oxidized to the former by ferrocenium triflate or air. [N3N]Mo(N2)[NaLx] reacts with Mo[N3N](OTf) to give [N3N]Mo(μ-N2)Mo[N3N], with triisopropylsilyl chloride to give [N3N]MoN=NSi(i-Pr)3, and with tributyltin chloride to give [N3N]MoN=NSn(Bu)3. An X-ray study of [N3N]MoN=NSi(i-Pr)3(space group P21/n, a= 13.524-(3) ?, b = 18.016(4) ?, c = 16.248(3) ?, β = 98.74(2)°, V = 3913(1) ?3 = 4, fw = 922.67, ρ(calcd) = 1.566 g/cm3, R = 0.069 Rw = 0.072) showed it to be a trigonal bipyramidal complex containing a slightly bent diazenido ligand (Mo-Nα = 1.788(9) ?, Mo-Nα-Nβ = 171.1(8)°, Nα-Nβ-Si = 154(1)°).
- Kol, Moshe,Schrock, Richard R.,Kempe, Rhett,Davis, William M.
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p. 4382 - 4390
(2007/10/02)
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