- Method for synthesizing 9, 10-dihydro-9-oxygen-10-phosphaphenanthrene-10-oxide
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The invention discloses a method for synthesizing 9, 10-dihydro-9-oxygen-10-phosphaphenanthrene-10-oxide. The method includes adding phosphorus trichloride into excessive o-phenylphenol drop by drop and carrying out esterification reaction to obtain phosphorous acid tri-orthophthalic phenyl ester; adding ZnCl2 catalysts into the phosphorous acid tri-orthophthalic phenyl ester, adding phosphorus trichloride into the phosphorous acid tri-orthophthalic phenyl ester drop by drop and carrying out acylation reaction to obtain 6-chlorine-(6 hydrogen)-dibenzo-(c, e)-oxygen phosphorus heterocyclic hexa-rings; sequentially carrying out hydrolysis reaction and cyclization reaction on the 6-chlorine-(6 hydrogen)-dibenzo-(c, e)-oxygen phosphorus heterocyclic hexa-rings to obtain the 9, 10-dihydro-9-oxygen-10-phosphaphenanthrene-10-oxide. The method has the advantages that the o-phenylphenol can be prevented from being volatilized or oxidized at high temperatures, the method is high in reaction speed and suitable for industrial production, and target products are high in yield and purity.
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Paragraph 0015; 0027; 0036; 0045; 0052-0054
(2018/02/04)
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- Solid-phase parallel synthesis of phosphite ligands
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Various routes for the synthesis of polymer-bound phosphites and phosphoramidites have been investigated. In the presence of a suitable activator the supported phosphoramidites react cleanly with alcohols to give the corresponding monodentate phosphite ligands in solution. We have applied this novel solid-phase route in the parallel synthesis of several monodentate chiral and achiral phosphite ligands.
- Swennenhuis, Bert H. G.,Chen, Ruifang,Van Leeuwen, Piet W. N. M.,De Vries, Johannes G.,Kamer, Paul C. J.
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supporting information; experimental part
p. 989 - 992
(2009/05/07)
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- Orthopalladated phosphinite complexes as high-activity catalysts for the suzuki reaction
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The synthesis of a range of phosphinite ligands PR2(OAr) (R = Ph, iPr), their simple complexes with palladium(II) and their palladacyclic complexes has been investigated. The crystal structure of one of the palladacyclic complexes, [{Pd(μ2-Cl)} {κ2-P, C-PiPr2(OC6H2-2,4-t Bu2)} 2], has been determined. The palladacyclic complexes show extremely high activity in the Suzuki coupling of aryl bromide substrates with phenylboronic acid and can also be used with alkylboronic acid substrates. A comparison of the phosphinite-based catalysts with equivalent phosphite- and phosphine-based systems highlights their superior activity. The orthometallation of the phosphinite ligand in the pre-catalyst appears to be crucial for optimal activity. While the phosphinite palladacycles are only moderately active in the coupling of activated and non-activated aryl chloride substrates, their tricyclohexylphosphine adducts prove to be highly active in the coupling of the deactivated substrate, 4-chloroanisole. This high activity compared with other palladacyclic systems is explained in terms of catalyst longevity. The orthometallated precatalysts appear to undergo a reductive activation process to generate zerovalent active catalysts via reductive elimination of the orthometallated ring with a phenyl introduced by the boronic acid. This implies that the true active catalysts contain 2-arylated ligands. Catalysts formed with such 2-arylated ligands tend to show markedly higher activity than their parent ligands.
- Bedford, Robin B.,Hazelwood, Samantha L. Welch,Horton, Peter N.,Hursthouse, Michael B.
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p. 4164 - 4174
(2007/10/03)
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- Use of Functionalized Ethylene Oligomers To Prepare Recoverable, Recyclable Nickel(0) Diene Cyclooligomerization Catalysts
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Polyethylene-bound alkyl diaryl and triaryl phosphites that act as ligands for homogeneous nickel (0) butadiene cyclooligomerization catalysts are described.The homogeneous nickel (0) catalysts prepared in the presence of these ligands are shown to have the same product selectivity and reactivity as similar nickel catalysts prepared from low molecular weight phosphite ligands in reactions carried out at 100 deg C.By varying the ligand/nickel ratio, it is possible to vary the product selectivity of these polyethylene-bound nickel(0) catalysts.High product selectivities (>90percent) for 1,5-cyclooctadiene are attainable.These ethylene oligomer ligated nickel(0) catalysts take advantage of the temperature-dependent solubility properties of polyethylene in order to maintain catalyst homogeneity at 100 deg C during the oligomerization.Recovery and recycling of the catalyst is possible because the catalyst and polyethylene quantitatively coprecipitate on cooling the reaction mixture to 25 deg C.
- Bergbreiter, David E.,Chandran, Rama
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p. 4754 - 4760
(2007/10/02)
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- On the mechanism of the nickel-catalysed regioselective cyclodimerization of isoprene
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A study of various Ni-ligand catalysed oligomerizations of isoprene has shown that with π-acidic P ligands the selectivity to cyclodimers amount to 97%. A new type of ligand is introduced, viz. fluoroalkyl phosphites having π-acceptor properties comparable to those of, e.g. PCl3. With tris(hexafluoroisopropyl) phosphite the main product is 1,4-dimethy1-4-vinylcyclohexene. A detailed explanation based on a two-step mechanism is given. As to the first step, for a series of ligands having similar steric properties the changes in product distribution as a function of the electronic ligand parameter are explained in terms of a gradual change in HOMO-LUMO interactions between Ni and the olefins, with strong π-acidic ligands promoting the head-to-head coupling of the isoprene molecules. The second step, involving reductive elimination of a cyclodimer from the metal, shows an increasing selectivity towards substituted cyclohexenes for the head-to-head and tail-to-tail intermediates with increasing π-acidity of the ligand. The qualitative orbital treatment presented as an explanation is also applicable to reactions found for other metallacyclopentanes.
- van Leeuwen,Roobeek
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p. 1973 - 1983
(2007/10/02)
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