- 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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- Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
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Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 to +1.79 V vs SCE. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN?-*, which can be used to activate reductively recalcitrant aryl chlorides (Ered ≈ -1.9 to -2.9 V vs SCE) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes.
- Cao, Jilei,Tang, Xinxin,Toh, Ren Wei,Wang, Han,Wu, Jie,Wu, Xiangyang,Xu, Jinhui,Yang, Xiaona,Yeow, Edwin K. L.,Zhou, Rong
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supporting information
p. 13266 - 13273
(2021/09/07)
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- Continuous synthesis method of tetraphenylphosphinophenylphenol salt
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The method uses triphenylphosphine, halogenated benzene and phenol as raw materials, and the sodium hydroxide solution is an acid binding agent. The preparation method comprises the following steps: triphenylphosphine. The halogenated benzene and the reaction solvent are mixed in a continuous flow reactor to prepare a tetraphenylhalogenated phosphine solution, a prepared tetraphenylhalogenated phosphine solution, phenol and sodium hydroxide solution with a concentration 32% are mixed in a continuous flow reactor to prepare a tetraphenylphosphine phenol salt. Compared with a conventional stirred tank reactor, the reactor used in the preparation method is smaller in size, simple to operate, continuous in reaction, high in yield, environmentally friendly, stable in pH value during reaction, relatively mild in reaction conditions and stable in prepared tetraphenylphenol salt.
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Paragraph 0022; 0027-0028
(2021/09/01)
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- Synthesis of Functional Monosilanes by Disilane Cleavage with Phosphonium Chlorides
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The Müller–Rochow direct process (DP) for the large-scale production of methylchlorosilanes MenSiCl4?n (n=1–3) generates a disilane residue (MenSi2Cl6?n, n=1–6, DPR) in thousands of tons annually. This report is on methylchlorodisilane cleavage reactions with use of phosphonium chlorides as the cleavage catalysts and reaction partners to preferably obtain bifunctional monosilanes MexSiHyClz (x=2, y=z=1; x,y=1, z=2; x=z=1, y=2). Product formation is controlled by the reaction temperature, the amount of phosphonium chloride employed, the choice of substituents at the phosphorus atom, and optionally by the presence of hydrogen chloride, dissolved in ethers, in the reaction mixture. Replacement of chloro by hydrido substituents at the disilane backbone strongly increases the overall efficiency of disilane cleavage, which allows nearly quantitative silane monomer formation under comparably moderate conditions. This efficient workup of the DPR thus not only increases the economic value of the DP, but also minimizes environmental pollution.
- Santowski, Tobias,Sturm, Alexander G.,Lewis, Kenrick M.,Felder, Thorsten,Holthausen, Max C.,Auner, Norbert
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supporting information
p. 3809 - 3815
(2019/02/13)
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- Long sought synthesis of quaternary phosphonium salts from phosphine oxides: Inverse reactivity approach
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Quaternary phosphonium salts (QPS), a key class of organophosphorus compounds, have previously only been available by routes involving nucleophilic phosphorus. We report the realisation of the opposite approach to QPS utilising phosphine oxides as the electrophilic partner and Grignard reagents as nucleophiles. The process is enabled through the crucial intermediacy of the derived halophosphonium salts. The route does not suffer from the slow kinetics and limited availability of many parent phosphines and a broad range of QPS were prepared in excellent yields.
- Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
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p. 5843 - 5846
(2018/06/13)
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- Solid state structure of Bi(N3)3, Bi(N 3)3·solvates and the structural dynamics in the [Bi(N3)6]3- anion
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The highly explosive bismuth triazide, Bi(N3)3, was obtained in pure form by the reaction of BiF3 with Me 3SiN3 in acetonitrile under solvothermal conditions at temperatures between 90 and 100 °C. X-ray, 14N NMR, infrared, and Raman spectra are discussed along with the data for the acetonitrile, acetone, and dmso adducts. The influence of the solvent on the purity of the azide products is studied in detail for Bi(N3)3 and the [Bi(N3)6]3- ion. Moreover, temperature dependent structural dynamics in the [Bi(N3)6] 3- ion, which is caused by small changes in the local environment around the [Bi(N3)6]3- ion in the solid state, was studied by temperature variable single crystal X-ray and Raman studies. The azido-chlorido ligand back exchange was studied in detail by NMR techniques in [Bi(N3)6]3- and Bi(N3)3 when chlorinated solvents such as CH2Cl2 were utilized leading to the formation of CH2(N3)Cl and/or HN 3 along with partially chlorinated bismuth azides.
- Rosenstengel, Kati,Schulz, Axel,Villinger, Alexander
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p. 6110 - 6126
(2013/07/05)
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- Phenylation of Organic Derivatives of Mercury, Silicon, Tin, and Bismuth with Pentaphenylantimony and Pentaphenylphosphorus
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Pentaphenylantimony and -phosphorus react with arylmercury chlorides in toluene at room temperature to give diaryl derivatives of mercury in yields of up to 95%. The reactions of pentaphenylantimony and -phosphorus with silicon and tin halides involve ary
- Sharutin,Sharutina,Senchurin,Egorova,Ivanenko,Petrov
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p. 202 - 203
(2007/10/03)
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- Preparation of organic phosphonium chloride
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An improved process for preparing an organic phosphonium chloride is performed by bringing an organic phosphonium bromide into contact with a chloride ion in a heterogeneous mixture solution of water and an organic solvent.
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- Thermal stability, decomposition paths, and Ph/Ph exchange reactions of [(Ph3P)2Pd(Ph)X] (X = I, Br, Cl, F, and HF2)
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Complexes of the type [(Ph3P)2Pd(Ph)X], where X = I (1), Br (2), Cl (3), F (4), and HF2 (5), possess different thermal stability and reactivity toward the Pd-Ph/P-Ph exchange reactions. While 1 decomposed (16 h) in toluene at 110 °C to [Ph4P]I, Pd metal, and Ph3P, complexes 2 and 3 exhibited no sign of decomposition under these conditions. Kinetic studies of the aryl-aryl exchange reactions of [(Ph3P)2Pd(C6D5)X] in benzene-de demonstrated that the rate of exchange decreases in the order 1 > 2 > 3, the observed rate constant ratio, kI:kBr:kCl, in benzene at 75 °C being ca. 100:4:1 for 1-d5, 2-d5, and 3-d5. The exchange was facilitated by a decrease in the concentration of the complex, polar media, and a Lewis acid, e.g., Et2O·BF3. Unlike [Bu4N]PF6, which speeded up the exchange reaction of 2-d5, [Bu4N]-Br inhibited it due to the formation of anionic four-coordinate [(Ph3P)Pd(C6D5)Br2]-. The latter and its iodo analogue were generated in dichloromethane and benzene upon addition of [Bu4N]X or PPN Cl to [(Ph3P)2Pd2(Ph)2(μ-X) 2] (X = I, Br, or Cl) and characterized in solution by 1H and 31P NMR spectral data. The mechanism of the aryl-aryl exchange reactions of [(Ph3P)2Pd(C6D5)X] in noncoordinating solvents of low polarity may not require Pd-X ionization but rather involves phosphine dissociation, the ease of which decreases in the order X = I > Br > Cl, as suggested by crystallographic data. Two mechanisms govern the thermal reactions of [(Ph3P)2Pd(Ph)F], 4. One of them is similar to the aryl-aryl exchange and decomposition path for 1-3, involving a tight ion pair intermediate, [Ph4P][(Ph3P)PdF], within which two processes were shown to occur. At 75 °C, the C-P oxidative addition restores the original neutral complex (4). At 90 °C, reversible fluoride transfer from Pd to the phosphonium cation resulted in the formation of covalent [Ph4PF] and [(Ph3P)Pd], which was trapped by PhI to produce [(Ph3P)2Pd2(Ph)2(μ-I) 2]. The other decomposition path of 4 leads to the formation of [(Ph3P)3Pd], Pd, Ph2 , Ph3PF2, and Ph2P-PPh2 as main products. Unlike the aryl-aryl exchange, this decomposition reaction is not inhibited by free phosphine. The formation of biphenyl was shown to occur due to PdPh/PPh coupling on the metal center. Mechanisms accounting for the formation of these products are proposed and discussed. The facile (4 h at 75 °C) thermal decomposition of [(Ph3P)2Pd(Ph)(FHF)] (5) in benzene resulted in the clean formation of PhH, Ph3PF2, Pd metal, and [(Ph3P)3Pd].
- Grushin, Vladimir V.
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p. 1888 - 1900
(2008/10/08)
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- Process for preparing diaryl carbonate
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A process for preparing a diaryl carbonate from a diaryl oxalate in a liquid phase by decarbonylation is conducted by the steps of: 1) performing a decarbonylation reaction of a diaryl oxalate in the presence of an organic phosphorus compound catalyst to give a reaction mixture of a diaryl carbonate and the organic phosphorus compound catalyst; 2) recovering the diaryl carbonate from the reaction mixture; and 3) performing a decarbonylation reaction of a diaryl oxalate in the presence of the reaction mixture from which the diaryl carbonate has been recovered and to which a halogen atom-containing compound is added, to give a reaction mixture of a diaryl carbonate and the organic phosphorus compound catalyst.
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