- trans-2,5-Dialkylpyrrolidinyl-containing phosphinamines. Synthetic and mechanistic studies in Pd-catalysed asymmetric allylic alkylation
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The preparation of new phosphinamine ligands possessing an enantiopure trans-2,5-dialkylpyrrolidinyl unit linked by a rigid o-phenylene bridge to a diphenylphosphine is described. Only that route forming the trans-2,5- dialkylpyrrolidine in the final step from (2-aminophenyl)diphenylphosphine proved successful. The cyclocondensation proceeded in 48% and 27% yields, respectively, for the dimethyl- and diethyl-analogues. Their palladium complexes were prepared and applied to the test of enantioselective alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate in high chemical yields but with moderate enantioselectivities of up to 34% ee. 1H NMR spectra of the η3-allyl Pd complexes of four trans-2,5- dialkylpyrrolidine-containing ligands were analysed in an attempt to explain the results obtained. In the cases of the 1,3-diphenylallyl complexes, two diastereomers were observed for all four ligands and their configurations were assigned with the aid of COSY and NOESY experiments. The catalytic results obtained are best interpreted by the reaction proceeding with nucleophilic attack on the allyl trans to the phosphorus donor atom of the major diastereomer.
- Cahill, John P.,Cunneen, Deirdre,Guiry, Patrick J.
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- Silver-Free Au(I) Catalysis Enabled by Bifunctional Urea- and Squaramide-Phosphine Ligands via H-Bonding
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A library of gold(I) chloride complexes with phosphine ligands incorporating pendant (thio)urea and squaramide H-bond donors was prepared with the aim of promoting chloride abstraction from Au(I) via H-bonding. In the absence of silver additives, complexes bearing squaramides and trifluoromethylated aromatic ureas displayed good catalytic activity in the cyclization of N-propargyl benzamides, as well as in a 1,6-enyne cycloisomerization, a tandem cyclization-indole addition reaction and the hydrohydrazination of phenylacetylene. Kinetic studies and DFT calculations indicate that the energetic span of the reaction is accounted by both the chloride abstraction step, facilitated by the bidentate H-bond donor via an associative mechanism, and the subsequent cyclization step.
- Echavarren, Antonio M.,Franchino, Allegra,Martí, àlex,Nejrotti, Stefano
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supporting information
p. 11989 - 11996
(2021/07/06)
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- Synthesis and biological evaluation of vanadium complexes as novel anti-tumor agents
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A class of vanadium complexes were prepared and investigated for their antiproliferative effects by MTT assay. The structure-activity relationship was extensively studied through the ligand variation. The results showed that the synthetic vanadium complexes demonstrated moderate to good antiproliferative activities against the four cancer cell lines including MGC803, EC109, MCF7 and HepG2, respectively. Of note was that most of the complexes showed preferential growth inhibitory activity to some degree toward gastric cancer line MGC803. Among them, complex 19 exhibited the most and broad-spectrum proliferative inhibition against the tested cell lines. In addition, mechanism studies illustrated that complex 19 could prevent the colony formation, migration and EMT process, as well as induce apoptosis of MGC803 cells. Furthermore, Western blot experiments revealed that the expression of apoptosis-related proteins changed, including up-regulation of Bax, PARP and caspase-3/9, as well as down-regulation of Bcl-2.
- Lu, Ling-Pan,Suo, Feng-Zhi,Feng, Ya-Li,Song, Li-Li,Li, Ying,Li, Yang-Jie,Wang, Kai-Ti
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- Phosphine-imine and-enamido ligands for acceptorless dehydrogenation catalysis
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A highly tunable phosphine-imine ligand family is introduced. Following metallation with ruthenium, deprotonation of the ligand affords a phosphine-enamido species. Complexes with the ligand in both the imine and enamido forms are active toward acceptorless dehydrogenation reactions.
- Stubbs,Firth,Bridge,Berger,Hazlehurst,Boyle,Blacquiere
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supporting information
p. 647 - 650
(2017/02/05)
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- Imine compound, novel catalyst for olefin polymerization, and method for producing olefin polymer
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Disclosed is a compound represented by the following general formula (1). In the formula, X represents a nitrogen atom, Y represents a nitrogen atom or a phosphorous atom, R5 and R6 independently represent C1-30 hydrocarbon groups which may contain a hydrogen atom or a hetero atom, and at least one of R5 and R6 is a hydrocarbon group having two or more hetero atom-containing groups, and R1 to R4 independently represent a hydrogen atom, a halogen atom or a C1-20 hydrocarbon group which may contain a hetero atom. A plurality of groups selected from the R1 to the R4 may be connected with one another to form aliphatic rings, aromatic rings or heterocycles containing hetero atoms selected from oxygen, nitrogen and sulfur. At the time, the number of ring members is 5-8, and the ring may have a substituent.
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Paragraph 0208; 0210
(2016/10/09)
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- Stabilized naked Sub-nanometric Cu clusters within a polymeric film catalyze C-N, C-C, C-O, C-S, and C-P bond-forming reactions
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Sub-nanometric Cu clusters formed by endogenous reduction of Cu salts and Cu nanoparticles are active and selective catalysts for C-N, C-C, C-O, C-S, and C-P bond-forming reactions. Sub-nanometric Cu clusters have also been generated within a polymeric film and stored with full stability for months. In this way, they are ready to be used on demand and maintain high activity (TONs up to 104) and selectivity for the above reactions. A potential mechanism for the formation of the sub-nanometric clusters and their electronic nature is presented.
- Oliver-Messeguer, Judit,Liu, Lichen,García-García, Saray,Canós-Giménez, Claudia,Domínguez, Irene,Gavara, Rafael,Doménech-Carbó, Antonio,Concepción, Patricia,Leyva-Pérez, Antonio,Corma, Avelino
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supporting information
p. 3894 - 3900
(2015/04/14)
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- Effect of triarylphosphane ligands on the rhodium-catalyzed hydrosilylation of alkene
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A series of triarylphosphanes (1a, 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, 10a, 11a) have been synthesized. An X-ray crystal structure analysis of (2-bromophenyl)diphenylphosphane (1a) unambiguously confirmed the constitution of the functionalized phosphane. The hydrosilylation reaction of styrene with triethoxysilane catalyzed with RhCl3/triarylphosphane was studied. In comparison with the classic Wilkinson's catalyst, rhodium complexes with functionalized triarylphosphane ligands are characterized by a very high catalytic effectiveness for the hydrosilylation of alkene. Among these catalysts tested, RhCl3/diphenyl(2-(trimethylsilyl)phenyl)phosphane (8a) exhibited excellent catalytic properties. Using this silicon-containing phosphane ligand for the rhodium-catalyzed hydrosilylation of styrene, both higher conversion of alkene and higher β-adduct selectivity were obtained than with Wilkinson's catalyst.
- Xue, Mei,Li, Jiayun,Peng, Jiajian,Bai, Ying,Zhang, Guodong,Xiao, Wenjun,Lai, Guoqiao
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p. 120 - 126
(2014/02/14)
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- General and selective copper-catalyzed reduction of tertiary and secondary phosphine oxides: Convenient synthesis of phosphines
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Novel catalytic reductions of tertiary and secondary phosphine oxides to phosphines have been developed. Using tetramethyldisiloxane (TMDS) as a mild reducing agent in the presence of copper complexes, PO bonds are selectively reduced in the presence of other reducible functional groups (FGs) such as ketones, esters, and olefins. Based on this transformation, an efficient one pot reduction/phosphination domino sequence allows for the synthesis of a variety of functionalized aromatic and aliphatic phosphines in good yields.
- Li, Yuehui,Das, Shoubhik,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 9727 - 9732
(2012/07/14)
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- Highly chemoselective metal-free reduction of phosphine oxides to phosphines
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Unprecedented chemoselective reductions of phosphine oxides to phosphines proceed smoothly in the presence of catalytic amounts of specific Br?nsted acids. By utilizing inexpensive silanes, e.g., PMHS or (EtO)2MeSiH, other reducible functional groups such as ketones, aldehydes, olefins, nitriles, and esters are well-tolerated under optimized conditions.
- Li, Yuehui,Lu, Liang-Qiu,Das, Shoubhik,Pisiewicz, Sabine,Junge, Kathrin,Beller, Matthias
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p. 18325 - 18329
(2013/01/15)
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- Microwave-assisted synthesis of phenylene-bridged aminophosphine ligands: Acceleration of N-arylation and aryl fluoride phosphorylation reactions
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(Chemical Equation Presented) Hindered β-aminoarylphosphines show promise as bidentate ligands for metal centers, but their reported synthesis requires heating at high temperatures for several days. Herein are reported conditions by which the two steps composing this synthesis, Buchwald-Hartwig amination and nucleophilic phosphorylation reactions, may both be completed in less than 3 h using microwave irradiation. The effects of several parameters on the outcome of the amination reaction are discussed, as are some indications of the scope within which each of these microwave protocols is effective.
- Seipel, Kelsey R.,Platt, Zed H.,Nguyen, Minh,Holland, Andrew W.
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p. 4291 - 4294
(2008/09/20)
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- New phosphine-functionalized N-heterocyclic carbene ligands for palladium-catalyzed hydroarylation reaction
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Novel triarylphosphine-functionalized imidazolinium salts have been prepared and successfully applied in palladium-catalyzed hydroarylation of bicyclic olefins. Under reductive conditions (HCOOH, Et3N), the complexes generated in situ from imidazolinium salts and Pd(OAc)2 catalyzed the hydroarylation of bicyclic alkenes with aryl iodides, providing the hydroarylation products with high turnover numbers (TON, up to 1.9-10 5) and turnover frequencies (TOF, up to 6.3-104). Georg Thieme Verlag Stuttgart.
- Zhong, Jun,Xie, Jian-Hua,Wang, Ai-E.,Zhang, Wei,Zhou, Qi-Lin
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p. 1193 - 1196
(2007/10/03)
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- Copper-catalyzed C-P bond construction via direct coupling of secondary phosphines and phosphites with aryl and vinyl halides
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(Matrix presented) A general method for the coupling of aryl and vinyl halides with diaryl and dialkyl phosphines, as well as with dibutyl phosphite, is reported. This highly efficient transformation is realized through the use of copper(I) iodide as a catalyst, N,N′-dimethylethylenediamine as a ligand, and Cs2CO3 as a base. A variety of sterically hindered and/or functionalized substrates were found to react under these reaction conditions to provide products in good to excellent yields.
- Gelman, Dmitri,Jiang, Lei,Buchwald, Stephen L.
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p. 2315 - 2318
(2007/10/03)
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- Rapid formation of triarylphosphines by microwave-assisted transition metal-catalyzed C-P cross-coupling reactions
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(matrix presented) Rapid, direct transition metal-catalyzed C-P(III) cross-coupling reactions were performed by microwave dielectric heating, employing diphenylphosphine and aryl halides/triflates as substrates. Depending on the specific aryl halide/triflate precursor, the highest yields were obtained utilizing heterogeneous or homogeneous Pd or Ni catalysts in DMF or NMP in the presence of KOAc or DABCO as a base.
- Stadler, Alexander,Kappe, C. Oliver
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p. 3541 - 3543
(2007/10/03)
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- A novel access to tertiary and secondary ortho-aminophenylphosphines by protected group synthesis and palladium catalyzed P-C coupling reactions
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The dilithium salt 1a formed by ortho-metallation of N-tert-butoxycarbonylaniline (BOC-aniline) 1 with two equivalents of tert-butyllithium reacts with the chlorophosphines Ph3-n,PCln, (n = 1 - 3) to yield the BOC protected ortho-aminophenylphosphines 2 - 4 in high yields. On deprotection of 2 - 4 with trimethylchlorosilane in the presence of phenol the HCl adducts of the ortho-aminophenylphosphines 5 - 7 are formed which may be deprotonated with KOH or NaOH to give the neutral phosphines 5a - 7a. The novel secondary phosphine 8 with two ortho-aminophenyl groups is accessible by cleavage of the P-C bond in 7a with metallic lithium and subsequent hydrolysis. The bifunctional P,N ligands 6 or 6a are alternatively accessible by Pd-catalyzed P-C coupling of ortho-iodoaniline with phenylphosphine. If a 1:1 stoichiometry is employed in the coupling reaction of ortho-iodoaniline and phenylphosphine the chiral secondary phosphine 9 is formed.
- He?ler, Antonella,Kottsieper, Konstantin W.,Schenk, Stefan,Tepper, Michael,Stelzer, Othmar
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p. 347 - 353
(2007/10/03)
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- Complexes of titanium and zirconium containing a tridentate linked amido-cyclopentadienyl ligand with a soft donor group: Synthesis, structure, and ethylene polymerization catalysis
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Group 4 metal complexes M(η5:η1-C5R4SiMe 2NCH2CH2SMe)Cl2 (R=H, M=Ti; R=Me, M=Ti, Zr) containing the thioether-functionalized linked amido-cyclopentadienyl ligand were synthesized and characterized by 1H- and 13C-NMR spectroscopy, mass spectrometry, and elemental analysis. The crystal structures of the complexes Ti(η5:η1-C5H4SiMe 2NCH2CH2SMe)Cl2 and Zr(η5:η1:η1-C5Me 4SiMe2NCH2CH2SMe)Cl2 were determined by single-crystal X-ray diffraction studies. The titanium complex is a conventional three-legged piano-stool molecule without an intramolecular interaction between the sulfur donor group and the titanium center, whereas the zirconium complex adopts a trigonal bipyramidal structure, with the five-membered ring and the coordinating methylthio group in the apical positions. Reaction between the titanium dibenzyl Ti(η5:η1-C5Me4ZNCH 2CH2SMe)(CH2Ph)2 (Z=SiMe2, CH2SiMe2) and B(C6F5)3 in C6D5Br resulted in the clean formation of the solvent-separated ion pair [Ti(η5:η1-C5Me4ZNCH 2CH2SMe)(η2-CH2Ph)] +[(PhCH2)B(C6F5)3] -. The dichloro complexes M(η5:η1-C5Me4SiMe 2NCH2CH2SMe)Cl2, when activated with methylaluminoxane, catalyzed the polymerization of ethylene with moderate activities. The phosphino-functionalized ligand C5Me4SiMe2NC6H4(PPh 2)-2 was also coordinated at titanium and zirconium centers; NMR spectroscopic data inferred an intramolecular metal-phosphine interaction for these M{η5:η1-C5Me4SiMe 2NC6H4(PPh2)-2}Cl2 complexes.
- Okuda, Jun,Eberle, Thomas,Spaniol, Thomas P.,Piquet-Faure, Valerie
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p. 127 - 137
(2007/10/03)
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- Synthesis and Resolution of Quinazolinone Atropisomeric Phosphine Ligands
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The syntheses of 2-methyl-3-[2′-(diphenylphosphino)phenyl]-4(3H)-quinazolinone (MPQ, 1a) and methyl-substituted analogues were achieved in good yield by coupling N-acetylanthranilic acid with the corresponding phosphinoanilines. Resolution of ligand 1b was achieved using (-)-di-μ-chlorobis-[(S)-dimethyl-(1-phenylethyl)aminato-C 2,N]dipalladium(II) (5). The resulting crystalline complex (S,R)-6 served to unambiguously assign the absolute configuration of antipode (R)-(-)-1b. A practical resolution of this series of ligands 1a-c was accomplished using the (benzenesulfonyl-)hydrazone derivative of camphorsulfonic acid (7) as a resolving agent.
- Dai, Xuedong,Wong, Audrey,Virgil, Scott C.
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p. 2597 - 2600
(2007/10/03)
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- Water soluble phosphines VIII. Palladium-catalyzed P-C cross coupling reactions between primary or secondary phosphines and functional aryliodides - A novel synthetic route to water soluble phosphines
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Tertiary phosphines Ph2P-Ar and PhP(Ar)2 containing mono-and disubstituted aromatic ring systems Ar (Ar = C6H4-X and C6H3-XY; X, Y = Me, OH, NH2, COOH, COOMe and SO3Na) are accessible in good yields by Pd(0)-catalyzed cross coupling reactions between diphenylphosphine or phenylphosphine and substituted aryliodides I-C6H4-X or I-C6H3-XY in organic solvents (dimethylacetamide, acetonitrile, methanol) using organic amines or potassium and sodium acetate as bases. If the primary phosphine is employed in the appropriate stoichiometric ratio, functionalized secondary phosphines, e.g. Ph(H)P-C6H4-p-SO3Na, may be obtained selectively.
- Herd, Oliver,Hessler, Antonella,Hingst, Martin,Tepper, Michael,Stelzer, Othmar
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- Preparation of Hybrid Bidentate Phosphine Ligands by Reduction of Their Benzyl- or Phenyl-phosphonium Salts. X-Ray Crystal Structure of 2-Aminophenyltriphenylphosphonium Tetrachloronickelate(II)
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The 2-substituted phenylphosphine bidentate hybrid ligands, 2-aminophenyl-, 2-methylaminophenyl-, 2-hydroxyphenyl- and (2-amino-3-methylphenyl)-diphenylphosphine, (1a-d), respectively, and 2-aminophenylmethylphenylphosphine, (1e), were synthesized by reduction of their phenylphosphonium halides, (2a-e)X (X = Cl or Br), with sodium naphthalenide in tetrahydrofuran at -68 deg, or electrochemically at a mercury cathode.The phosphonium salts were prepared by reaction of triphenylphosphine with aryl halide and anhydrous nickel halide at 200 deg.X-Ray diffraction of (2a)2 showed it to have monoclinic space group P21/n, a 10.657(4), b 20.966(3), c 20.422(6) Angstroem, β 101.33(2) deg and Z 4.The structure was refined by a full-matrix least-squares procedure to a final R 0.050 for 3534 reflections with I > 2.5?(I).
- Cooper, Mervyn K.,Downes, J. Michael,Duckworth, Paul A.,Tiekink, Edward R. T.
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p. 595 - 609
(2007/10/02)
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