- The basicity of phosphines
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The basicities of the triarylphosphines P(4-XC6H4)3 (X = Cl, F, H, CH3, CH3O, (CH3)2N), P(3-CH3C6H4)3, and P(2-CH3C6H7)3 as well as the trialkylphosphines P(t-Bu)3 and PCy3 have been measured by the nitromethane titration method.The range of basicity available by aryl substitution is very large, being pKa = 8. 65 for X = (CH3)2N to 1.03 for X = Cl.The most basic phosphine is P(t-Bu)3 whose pKa = 11.40.The measured basicities correlate well wit ?p, ?Φ, and ν as well as with the lone pair ionisation potentials of the triarylphosphines.Generally the 1H,31P, and 13C nmr spectral parameters of the free and protonated phosphines do not correlate well with pKa.
- Allman, Tim,Goel, Ram G.
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- Electrophilic Phosphonium Cation-Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen
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The metal-free reduction of phosphane oxides with molecular hydrogen (H2) using oxalyl chloride as activating agent was achieved. Quantum-mechanical investigations support the heterolytic splitting of H2 by the in situ formed electrophilic phosphonium cation (EPC) and phosphane oxide and subsequent barrierless conversion to the phosphane and HCl. The reaction can also be catalyzed by the frustrated Lewis pair (FLP) consisting of B(2,6-F2C6H3)3 and 2,6-lutidine or phosphane oxide as Lewis base. This novel reduction was demonstrated for triaryl and diaryl phosphane oxides providing access to phosphanes in good to excellent yields (51–93 %).
- Stepen, Arne J.,Bursch, Markus,Grimme, Stefan,Stephan, Douglas W.,Paradies, Jan
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- Palladium-Catalyzed Diastereoselective Synthesis of (Z)-Conjugated Enynyl Homoallylic Alcohols
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The diastereoselective synthesis of anti-homoallylic alcohols bearing conjugated (Z)-enynes through a palladium-catalyzed three-component reaction is described. This reaction features a broad substrate scope, good functional group compatibility, and high levels of (Z)-alkene stereocontrol. In this reaction, Pd(0) functions as a catalyst in two fundamental steps of the tandem sequence: 1) the generation of a borylated π-allylpalladium species from bifunctional conjunctive reagents, inducing umpolung allylation of aldehydes, and 2) C(sp2)?C(sp) cross-coupling. Further transformations of the obtained products highlight their synthetic utility. (Figure presented.).
- Horino, Yoshikazu,Ishibashi, Mayo,Sakamoto, Juri,Murakami, Miki,Korenaga, Toshinobu
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- Synthesis, gallium-68 radiolabelling and biological evaluation of a series of triarylphosphonium-functionalized DO3A chelators
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Radiolabelled lipophilic cations that accumulate in mitochondria according to the magnitude of the mitochondrial membrane potential can be used to report non-invasively on mitochondrial dysfunction in cardiovascular disease, cardiotoxicity, and cancer. While several such cations are already commercially available for SPECT imaging, PET offers greater promise in terms of sensitivity, resolution, and capacity for dynamic imaging and pharmacokinetic modelling. We have therefore synthesised a series of three triarylphosphonium-functionalised DO3A chelators for positron emitter gallium-68, with differing alkyl-functionalisation motifs to provide opportunities for tunable lipophilicity as a means of optimising their pharmacokinetics. To assess their capacity to report on mitochondrial membrane potential, we assessed their pharmacokinetic profiles in isolated tumour cells and isolated perfused rat hearts before and after mitochondrial depolarisation with the ionophore CCCP. All three compounds radiolabelled with over 97% RCY and exhibited log?D values of between ?3.12 and ?1.81. In vitro assessment of the uptake of the radiotracers in cultured tumour cells showed a three-fold increase in uptake compared to unchelated [68Ga]Ga(iii). However, each complex exhibited less than 1% retention in healthy hearts, which was not significantly diminished by mitochondrial depolarisation with CCCP. This preliminary work suggests that while this approach is promising, the lipophilicity of this class of tracers must be increased in order for them to be useful as cardiac or cancer imaging agents.
- Smith, Adam J.,Gawne, Peter J.,Ma, Michelle T.,Blower, Philip J.,Southworth, Richard,Long, Nicholas J.
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- Reduction of phosphine oxides to the corresponding phosphine derivatives in Mg/Me3SiCl/DMI system
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Direct reductions of phosphine oxides to the corresponding phosphines were performed successfully by using Mg/Me3SiCl/DMI system. The reduction proceeded under mild conditions and was applicable to a wide range of phosphine oxides; triarylphosphine oxides, alkyldiarylphosphine oxides, and dialkylarylphosphine oxides gave the corresponding phosphines in good to excellent yields.
- Kuroboshi, Manabu,Kita, Toshihito,Aono, Asuka,Katagiri, Toshimasa,Kikuchi, Seiya,Yamane, Syoko,Kawakubo, Hiromu,Tanaka, Hideo
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- Metal-free reduction of tertiary phosphine oxides with Hantzsch ester
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The (COCl)2/Hantzsch ester is found to be an effective system for the metal-free reduction of tertiary phosphine oxides. The reaction proceeds under mild conditions, and is applicable to triarylphosphine oxides and alkyldiarylphosphine oxides to produce the corresponding tertiary phosphines in good to excellent yields. This new finding provides a practical, convenient and metal-free method for the reduction of tertiary phosphine oxides to tertiary phosphines, and shows potential application in organic synthesis.
- Zhang, Tong-Xin,Zhang, Wei-Xi,Luo, Mei-Ming
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- Electroreduction of triphenylphosphine oxide to triphenylphosphine in the presence of chlorotrimethylsilane
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Electroreduction of triphenylphosphine oxide to triphenylphosphine in an acetonitrile solution of tetrabutylammonium bromide in the presence of chlorotrimethylsilane was performed successfully in an undivided cell fitted with a zinc anode and a platinum cathode under constant current. A plausible mechanism involving, (1) one-electron reduction of triphenylphosphine oxide generating the corresponding anion radical [Ph3P-O-], (2) subsequent reaction with chlorotrimethylsilane affording the (trimethylsiloxy)triphenylphosphorus radical [Ph3P-OSiMe 3], and (3) further one-electron reduction followed by P-O bond fission leading to triphenylphosphine is proposed. In a similar manner, electroreduction of some triarylphosphine oxides and alkyldiarylphosphine oxides was executed to give the corresponding phosphine derivatives in good to moderate yields. Georg Thieme Verlag Stuttgart · New York.
- Kawakubo, Hiromu,Kuroboshi, Manabu,Yano, Tomotake,Kobayashi, Kazuma,Kamenoue, Syogo,Akagi, Tomomi,Tanaka, Hideo
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- Mild Reduction of Phosphine Oxides with Phosphites To Access Phosphines
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A new method for the iodine-catalyzed reduction of phosphine oxides with phosphites at room temperature is reported. The mild reaction conditions, scalability, and simple purification requirements render it a method of choice for the large-scale production and facile regeneration of a variety of phosphines. Mechanistic studies, supported by DFT calculations of the oxygen transfer between the starting phosphine oxide and the phosphite reagent, are also presented. Such transmutations of phosphorus species were previously unknown.
- Li, Peng,Wischert, Raphael,Métivier, Pascal
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- FORMATION OF BENZOIC ACID IN THE PALLADIUM(II) CATALYZED CLEAVAGE OF PHENYL-ANTIMONY AND PHENYL-PHOSPHORUS GROUPS OF Ph3Sb AND Ph3P
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Palladium (II) catalyzed cleavage of phenyl-antimony and phenyl-phosphorus groups of Ph3Sb and Ph3P under carbon-dioxide or CO/NO atmosphere leading to benzoic acid, has been demonstrated.
- Goel, Anil B.,Richards, H. J.,Kyung, J. H.
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- Superbase-Assisted Selective Synthesis of Triarylphosphines from Aryl Halides and Red Phosphorus: Three Consecutive Different SNAr Reactions in One Pot
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Aryl halides, ArX (Ar = Ph, 2-, 3- and 4-Tol, 1- and 2-Np, 4-C6H4CONH2; X = F, Cl, Br), rapidly and exothermically (100–180 °C, 0.5–2 h) react with red phosphorus in superbase systems KOH/L, where L is a polar nonhydroxylic complexing solvent (ligand), such as NMP, DMSO, HMPA, to afford the corresponding triarylphosphines (Ar3P) in up to 74 % yield (for X = F). Thus, three consecutive reactions of SNAr (aromatic nucleophilic substitution) to form the three C(sp2)–P bonds are realized in one pot. The synthesis is mostly chemoselective (with rare exception): neither mono- nor diphosphines have been isolated. The best results were attained when aryl fluorides were treated with red phosphorus (Pn) in the KOH/NMP superbase system. This environmentally friendly, PCl3-free synthesis of Ar3P from available starting materials opens an easy and straightforward access to triarylphosphines, which are important ligands, synthetic auxiliaries, and components of high-tech- and medicinally oriented complexes.
- Malysheva, Svetlana F.,Kuimov, Vladimir A.,Belogorlova, Natalia A.,Albanov, Alexander I.,Gusarova, Nina K.,Trofimov, Boris A.
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- An acidity scale of tetrafluoroborate salts of phosphonium and iron hydride compounds in [D2]dichIoromethane
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Equilibrium constants (K) for reactions between acids and the conjugate base forms of a number of phosphonium salts, [HPR3][BF4], and iron hydrides, [Fe(CO)3H(PR3)2][BF 4], in CD2Cl2 have been determined by means of 31P and 1H NMR spectroscopy at 20°C. The anchor compound chosen for pKCD2Cl2 determinations was [HPCy 3][BF4] with a pKCD2Cl2 value of 9.7, as assigned by literature convention (Cy: cyclohexyl). A continuous scale of pKCD2Cl2 values covering the range from 9.7 to -3 was created and correlated with the ΔH values reported by Angelici and co-workers and literature pKa values. The pKCD2Cl2 values for 15 other hydride or dihydrogen complexes of the iron group elements and of diethyl ether were also placed on this scale. The crystal structures of [Fe(CO) 3H(PCy2Ph)2][BF4] and [Fe(CO) 3(PCy2Ph)2] revealed that the frans-oriented, bulky, unsymmetrical phosphane ligands distort the equatorial plane of the complexes. The acidity of iron carbonyl hydrides is an important feature of the reactions of iron hydrogenase enzymes.
- Li, Tianshu,Lough, Alan J.,Morris, Robert H.
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- Photochemical transformation of chlorobenzenes and white phosphorus into arylphosphines and phosphonium salts
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Chlorobenzenes are important starting materials for the preparation of commercially valuable triarylphosphines and tetraarylphosphonium salts, but their use for the direct arylation of elemental phosphorus has been elusive. Here we describe a simple photochemical route toward such products. UV-LED irradiation (365 nm) of chlorobenzenes, white phosphorus (P4) and the organic superphotoreductant tetrakis(dimethylamino)ethylene (TDAE) affords the desired arylphosphorus compounds in a single reaction step.
- Gschwind, Ruth M.,Mende, Michael,Scott, Daniel J.,Streitferdt, Verena,Till, Marion,Wolf, Robert
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supporting information
p. 1100 - 1103
(2022/02/03)
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- Palladium-Catalyzed C-P(III) Bond Formation by Coupling ArBr/ArOTf with Acylphosphines
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Palladium-catalyzed C-P bond formation reaction of ArBr/ArOTf using acylphosphines as differential phosphination reagents is reported. The acylphosphines show practicable reactivity with ArBr and ArOTf as the phosphination reagents, though they are inert to the air and moisture. The reaction affords trivalent phosphines directly in good yields with a broad substrate scope and functional group tolerance. This reaction discloses the acylphosphines' capability as new phosphorus sources for the direct synthesis of trivalent phosphines.
- Chen, Xingyu,Wu, Hongyu,Yu, Rongrong,Zhu, Hong,Wang, Zhiqian
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p. 8987 - 8996
(2021/06/30)
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- Synthesis method of phosphine (III) compound
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The invention aims to provide an aryl phosphine oxide compound as a raw material, wherein P=O keys are activated by an acid anhydride and alkali is continued. The preparation of the phosphine (III) compound is carried out under the action of a crown ether and a reducing agent. The method has the advantages of cheap and easily available raw materials, simple operation, high atomic economy and the like. Compared with a traditional reduction mode, the method is ingenious in design, waste emission is reduced, separation of intermediate products is omitted, and related reagents such as silicon hydrogen, aluminum, boron and the like with higher price can be avoided. And the reaction suitability is extensive.
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Paragraph 0020
(2021/11/27)
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- Synthesis method of triphenylphosphine derivative tri-(R-phenyl) phosphine
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The invention relates to a synthesis method of a triphenylphosphine derivative tri-(R-phenyl) phosphine. The synthesis method comprises the following steps: adding magnesium chips, a solvent and R-substituted halobenzene into a reaction kettle under the protection of nitrogen, initiating a reaction at a proper temperature, and dropwise adding an R-substituted halobenzene solution to synthesize anintermediate; dropwise adding a phosphorus trichloride solution to complete a Grignard reaction; dropwise adding diluted hydrochloric acid for hydrolysis after negative-pressure desolvation; and carrying out post-treatment to obtain TRPP. According to the method, the tri-(R-phenyl) phosphine of which the purity is greater than 99% is obtained with high selectivity and high yield.
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Paragraph 0049-0055; 0063-0064
(2020/11/09)
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- Organocatalyzed Reduction of Tertiary Phosphine Oxides
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A novel selective catalytic reduction method of tertiary phosphine oxides to the corresponding phosphines has been developed. Notably, the reaction proceeds smoothly with low catalyst loadings of 1-5 mol% even at low temperature (70 C). Under the optimized conditions various phosphine oxides could be selectively reduced and the desired phosphines were usually obtained in excellent yields above 90%. Furthermore, we have developed a one-pot reaction sequence for the preparation of valuable phosphinborane adducts. Simple addition of BH3THF subsequent to the reduction step gave the desired adducts in yields up to 99%.
- Schirmer, Marie-Luis,Jopp, Stefan,Holz, Jens,Spannenberg, Anke,Werner, Thomas
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supporting information
p. 26 - 29
(2016/01/25)
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- Atom Economic Ruthenium-Catalyzed Synthesis of Bulky β-Oxo Esters
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Ruthenium complexes with the formulae Ru(CO)2(PR3)2(O2CPh)2 [6a-h; R=n-Bu, p-MeO-C6H4, p-Me-C6H4, Ph, p-Cl-C6H4, m-Cl-C6H4, p-CF3-C6H4, m,m′-(CF3)2C6H3] were prepared by treatment of triruthenium dodecacarbonyl [Ru3(CO)12] with the respective phosphine and benzoic acid or by the conversion of Ru(CO)3(PR3)2 (8e-h) with benzoic acid. During the preparation of 8, ruthenium hydride complexes of type Ru(CO)(PR3)3(H)2 (9g, h) could be isolated as side products. The molecular structures of the newly synthesized complexes in the solid state are discussed. Compounds 6a-h were found to be highly effective catalysts in the addition of carboxylic acids to propargylic alcohols to give valuable β-oxo esters. The catalyst screening revealed a considerably influence of the phosphine′s electronic nature on the resulting activities. The best performances were obtained with complexes 6g and 6h, featuring electron-withdrawing phosphine ligands. Additionally, catalyst 6g is very active in the conversion of sterically demanding substrates, leading to a broad substrate scope. The catalytic preparation of simple as well as challenging substrates succeeds with catalyst 6g in yields that often exceed those of established literature systems. Furthermore, the reactions can be carried out with catalyst loadings down to 0.1mol% and reaction temperatures down to 50 C.
- Jeschke, Janine,Korb, Marcus,Rüffer, Tobias,G?bler, Christian,Lang, Heinrich
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supporting information
p. 4069 - 4081
(2016/01/25)
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- Dual [Fe+Phosphine] catalysis: Application in catalytic wittig olefination
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Iron hydride complexes of the general formula P2Fe(NO)CO)H are highly active catalysts for the hydrosilylation of aldehydes or ketones and phosphine oxides. Depending on the solvent, the in situ reduction of the phosphine oxide can be faster than the corresponding hydrosilylation of a carbonyl group. This unusual activity was used within the context of catalytic Wittig olefination. Picture perfect: Iron hydride complexes of the general formula P2Fe(NO)CO)H are highly active catalysts for the hydrosilylation of aldehydes or ketones and phosphine oxides. Depending on the solvent, the in situ reduction of the phosphine oxide can be faster than the corresponding hydrosilylation of a carbonyl group. This unusual activity is used within the context of catalytic Wittig olefination. EWG=Electron-withdrawing group.
- Rommel, Susanne,Belger, Christian,Begouin, Jeanne-Marie,Plietker, Bernd
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p. 1292 - 1301
(2015/04/27)
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- Highly efficient reduction of tertiary phosphine oxides and sulfides with amine-assisted aluminum hydrides under mild conditions
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Reduction of tertiary phosphine oxides and sulfides into the corresponding phosphines with amine-assisted aluminum hydrides has been studied. The method is characterized by mild conditions, short reaction time, high efficiency, and expanded substrate scope. The new method is an alternative to the currently used methods of reducing phosphine oxides or recycling phosphines engaged in organic reactions.
- Yang, Shuyan,Han, Xinxin,Luo, Minmin,Gao, Jing,Chu, Wenxiang,Ding, Yuqiang
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p. 1156 - 1160
(2015/06/30)
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- Highly Active and Selective Ethylene Oligomerization Catalyst and Method of Preparing Hexene or Octene Using the Same
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This invention relates to a chromium complex compound for selective ethylene oligomerization including a chiral ligand, and to a method of selectively preparing 1-hexene or 1-octene from ethylene using the same.
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Page/Page column 9
(2012/06/01)
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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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scheme or table
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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- PROCESS FOR PRODUCTION OF PHOSPHINE DERIVATIVE FROM PHOSPHINE OXIDE DERIVATIVE
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Disclosed is a process for producing a phosphine derivative from a phosphine oxide derivative, which comprises the following steps: (I) mixing a phosphine oxide derivative represented by formula (1) with a chlorinating agent in a polar organic solvent to cause the reaction between these components; and (II-1) adding a salt of a metal having an ionization tendency equal to or lower than that of aluminum to the reaction mixture and carrying out the reductive reaction in the presence of aluminum or (II-2) subjecting the reaction mixture to electrolytic reduction, thereby producing a phosphine derivative represented by formula (2). ArnR3-nP═O (1) ArnR3-nP (2) In formulae (1) and (2), Ar represents an aryl group such as a phenyl group, a phenyl group having a substituent, a heteroaromatic ring group, and a heteroaromatic ring group having a substituent; R represents an aliphatic hydrocarbon group or an aliphatic hydrocarbon group having a substituent; and n represents an integer of 0 to 3.
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(2011/04/18)
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- Electroreduction of tetra-coordinate phosphonium derivatives; One-pot transformation of triphenylphosphine oxide into triphenylphosphine
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Electroreduction of triphenylphosphine dichloride in acetonitrile was performed successfully in an undivided cell fitted with an aluminium sacrificial anode and a platinum cathode, wherein Al3+, which was electrogenerated at the anode would react as a Lewis acid with triphenylphosphine dichloride to afford tetra-coordinate chlorotriphenylphosphonium species and subsequent two-electron reduction at the cathode would give triphenylphosphine. One-pot transformation of triphenylphosphine oxide to triphenylphosphine was achieved successfully by the treatment of triphenylphosphine oxide with oxalyl chloride and subsequent electroreduction. In a similar manner, some tetra-coordinate triphenylphosphonium species derived from triphenylphosphine oxide were reduced electrochemically to triphenylphosphine in moderate yields.
- Kuroboshi, Manabu,Yano, Tomotake,Kamenoue, Shogo,Kawakubo, Hiromu,Tanaka, Hideo
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experimental part
p. 5825 - 5831
(2011/09/12)
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- Synthesis of symmetrical and unsymmetrical functionalized arylphosphines from chlorophosphines and organozinc reagents
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A stepwise procedure allowing the formation of symmetrical arylphosphines is described. It relies on the use of preformed functionalized aromatic organozinc reagents to perform arylations of chlorophosphines. Some preliminary results concerning the synthesis of unsymmetrical diarylphenylphosphines through sequential coupling of organozinc species with dichlorophenylphosphine are also reported. Georg Thieme Verlag Stuttgart.
- Le Gall, Erwan,Ben A?ssi, Karima,Lachaise, Isabelle,Troupel, Michel
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p. 954 - 956
(2007/10/03)
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- Tetra-arylfluorophosphoranes
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A number of novel tetra-arylfluorophosphoranes have been synthesised.The most stable form of these compounds is the ionic form PR4+F- (R=aryl) although various other forms have been shown to exist including a molecular monomer PR4F and a dimer PR4+PR4F2-.The i.r. spectra of the ionic forms reveal strong P+...F- interactions.The fluorides are prepared via the hydrogendifluorides PR4+HF2- which contain distorted HF2- ions.
- Brown, Stephen J.,Clark, James H.,Macquarrie, Duncan J.
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p. 277 - 280
(2007/10/02)
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- Selective formation of ethanol from methanol, hydrogen and carbon monoxide
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A process for the selective formation of ethanol which comprises contacting methanol, hydrogen and carbon monoxide with a catalyst system comprising cobalt acetylacetonate, a tertiary organo Group V A compound of the periodic Table, a first promoter comprising an iodine compound and a second promoter comprising a ruthenium compound.
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