- Investigation of rhodium catalyzed hydroformylation of ethylene in supercritical carbon dioxide by in situ FTIR spectroscopy
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The reactions of RhH(CO)L3 (L=P(3,5-(CF3)2C6H3)3) with CO, H2, C2H4 and mixtures of these in supercritical carbon dioxide (scCO2) were investigat
- Haji, Shaker,Erkey, Can
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- Alkyne Aminopalladation/Heck and Suzuki Cascades: An Approach to Tetrasubstituted Enamines
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Alkyne aminopalladation reactions starting from tosylamides are reported. The emerging vinylic Pd species are converted either in an intramolecular Heck reaction with olefinic units or in an intermolecular Suzuki reaction by using boronic acids exhibiting broad functional group tolerance. Tetra(hetero)substituted tosylated enamines are obtained in a simple one-pot process.
- Geffers, Finn J.,Jones, Peter G.,Kurth, Florens R.,Werz, Daniel B.
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supporting information
p. 14846 - 14850
(2021/10/19)
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- Systematic Study of the Stereoelectronic Properties of Trifluoromethylated Triarylphosphines and the Correlation of their Behaviour as Ligands in the Rh-Catalysed Hydroformylation
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The stereoelectronic properties of a series of trifluoromethylated aromatic phosphines have been studied using different approaches. The σ-donating capability has been evaluated by nuclear magnetic resonance (NMR) spectroscopy of the selenide derivatives and the protonated form of the different trifluoromethylated phosphines. The coupling constants between phosphorous and selenium (1JSeP) and phosphorous and hydrogen (1JHP) can be predicted by empirical equations and correlate the basicity of the phosphines with the number and relative position of trifluoromethyl groups. In contrast, the π-acceptor character of the ligands has been evaluated by measuring the frequency of the CO vibration in the infrared (IR) spectra of the corresponding Vaska type iridium complexes ([IrCl(CO)(PAr3)2], PAr3=triarylphosphine). Moreover, the correlation between the electronic properties and the performance of these phosphines as ligands in the rhodium-catalysed hydroformylation of 1-octene has been established. Phosphines with the lowest basicity, that are those with the highest number of trifluoromethyl groups, gave rise to more active catalytic systems.
- Herrera, Daniel,Peral, Daniel,Cordón, Mercedes,Bayón, J. Carles
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supporting information
p. 354 - 363
(2020/12/30)
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- Chemoselective Reduction of Phosphine Oxides by 1,3-Diphenyl-Disiloxane
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Reduction of phosphine oxides to the corresponding phosphines represents the most straightforward method to prepare these valuable reagents. However, existing methods to reduce phosphine oxides suffer from inadequate chemoselectivity due to the strength of the P=O bond and/or poor atom economy. Herein, we report the discovery of the most powerful chemoselective reductant for this transformation to date, 1,3-diphenyl-disiloxane (DPDS). Additive-free DPDS selectively reduces both secondary and tertiary phosphine oxides with retention of configuration even in the presence of aldehyde, nitro, ester, α,β-unsaturated carbonyls, azocarboxylates, and cyano functional groups. Arrhenius analysis indicates that the activation barrier for reduction by DPDS is significantly lower than any previously calculated silane reduction system. Inclusion of a catalytic Br?nsted acid further reduced the activation barrier and led to the first silane-mediated reduction of acyclic phosphine oxides at room temperature.
- Buonomo, Joseph A.,Eiden, Carter G.,Aldrich, Courtney C.
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supporting information
p. 14434 - 14438
(2017/10/23)
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- Superstable palladium(0) complex as an air-and thermostable catalyst for Suzuki coupling reactions
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An unprecedentedly thermo-and air-stable Pd0 complex from readily available electron-poor trifluoromethylated phosphine was serendipitously discovered. As detailed and comparative DFT calculations indicate, the stability of the complex is associated with unusually strong ligand-ligand noncovalent interactions. The unique stability and the presence of hydrophobic structural elements of the complex offer several practical advantages, which were exploited in catalytic Suzuki-Miyaura coupling reactions.
- Jakab, Alexandra,Dalicsek, Zoltn,Holczbauer, Tams,Hamza, Andrea,Ppai, Imre,Finta, Zoltn,Timri, Gza,Sos, Tibor
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supporting information
p. 60 - 66
(2015/02/02)
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- Stereospecific deoxygenation of phosphine oxides with retention of configuration using triphenylphosphine or triethyl phosphite as an oxygen acceptor
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(Chemical Equation Presented) A new protocol for deoxygenation of various phosphine oxides with retention of configuration is described. The advantage of the new method includes milder conditions and considerably shortened reaction times. Mechanistic studies about the oxygen transfer between the starting phosphine oxide and the sacrificial triphenylphosphine are also presented.
- Wu, Hai-Chen,Yu, Jin-Quan,Spencer, Jonathan B.
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p. 4675 - 4678
(2007/10/03)
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- 1-bromo-3,5-bis(trifhioromethyl)benzene: A versatile starting material for organometallic synthesis
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1-Bromo-3,5-bis(trifluoromethyl)benzene (1) can be selectively prepared by treatment of 1,3-bis(fluorornethyl)benzene with N,N′-dibromo-5,5-dimethylhydantoin in strongly acidic media. A number of synthetically useful reactions via 3,5bis{trifluoromethyl)phenylmagnesium, -lithium, and -copper intermediates were accomplished. VCH Verlagsgesellschaft mbH, , 1996.
- Porwisiak, Jacek,Schlosser, Manfred
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p. 233 - 235
(2007/10/02)
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- On the Configurational and Substituent Dependence of the Pt-Cl Stretching Frequencies and of the 31P NMR Parameters in Substituted cis- and trans-Dichlorobis(triphenylphosphane)platinum(II) Compounds
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Correlations between substituent constants ?, Pt-Cl vibrational frequencies and 31P NMR parameters 1J195Pt,31P> and δ31P> for compounds of the type cis- and trans-2Cl2> (aryl, aryl',
- Alt, Helmut G.,Baumgaertner, Reinhard,Brune, Hans Albert
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p. 1694 - 1703
(2007/10/02)
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