- 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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- The Trityl-Cation Mediated Phosphine Oxides Reduction
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Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]? as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes. (Figure presented.).
- Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
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supporting information
p. 3035 - 3043
(2021/05/10)
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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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- 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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- Photocatalytic Arylation of P4 and PH3: Reaction Development Through Mechanistic Insight
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Detailed 31P{1H} NMR spectroscopic investigations provide deeper insight into the complex, multi-step mechanisms involved in the recently reported photocatalytic arylation of white phosphorus (P4). Specifically, these studies have identified a number of previously unrecognized side products, which arise from an unexpected non-innocent behavior of the commonly employed terminal reductant Et3N. The different rate of formation of these products explains discrepancies in the performance of the two most effective catalysts, [Ir(dtbbpy)(ppy)2][PF6] (dtbbpy=4,4′-di-tert-butyl-2,2′-bipyridine) and 3DPAFIPN. Inspired by the observation of PH3 as a minor intermediate, we have developed the first catalytic procedure for the arylation of this key industrial compound. Similar to P4 arylation, this method affords valuable triarylphosphines or tetraarylphosphonium salts depending on the steric profile of the aryl substituents.
- Cammarata, Jose,Gschwind, Ruth M.,Lennert, Ulrich,Rothfelder, Robin,Scott, Daniel J.,Streitferdt, Verena,Wolf, Robert,Zeitler, Kirsten
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supporting information
p. 24650 - 24658
(2021/10/14)
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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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supporting information
p. 15253 - 15256
(2018/10/24)
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- Ir(III)-catalyzed direct C-H functionalization of arylphosphine oxides: A strategy for MOP-type ligands synthesis
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Diazo compounds as coupling partners are efficiently applied to Ir(III)-catalyzed direct C-H functionalization of arylphos-phine oxides. Involving C-H activation, carbene insertion, and tautomerism, this reaction proceeds under mild conditions, thus proving an approach to the synthesis of MOP-type ligand precursor in a single step. The utility of this transformation has been further demonstrated in ligand synthesis as well as in the construction of phosphole framework.
- Liu, Zhong,Wu, Ji-Qiang,Yang, Shang-Dong
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supporting information
p. 5434 - 5437
(2017/11/06)
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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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- Single electron transfer-induced coupling of alkynylzinc reagents with aryl and alkenyl iodides
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Alkynylzinc reagents were found to undergo coupling with aryl and alkenyl iodides to give arylalkynes and alkenylalkynes without the aid of transition metals. The coupling reaction proceeds through a single electron transfer mechanism, where a substoichiometric amount of a phosphine works as an indispensable activator.
- Okura, Keisho,Kawashima, Hitomi,Tamakuni, Fumiko,Nishida, Naoya,Shirakawa, Eiji
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supporting information
p. 14019 - 14022
(2016/12/09)
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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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- 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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- Reduction of tertiary phosphine oxides with DIBAL-H
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(Chemical Equation Presented) The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-II) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed.
- Busacca, Carl A.,Raju, Ravinder,Grinberg, Nelu,Haddad, Nizar,James-Jones, Paul,Lee, Heewon,Lorenz, Jon C.,Saha, Anjan,Senanayake, Chris H.
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p. 1524 - 1531
(2008/04/12)
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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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- Oxidation-resistant cyclophosphazene fluid including triarylphosphine or phosphine oxide
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The oxidation resistance of a cyclophosphazene-based fluid (such as a lubricant or a hydraulic fluid) can be improved by the addition to the fluid of an oxidation-inhibiting amount of an aryl phosphine or phosphine oxide. The aryl phosphine or phosphine o
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- N-Phenyl-P,P,P-triarylphospha-λ5-azenes, Triarylphosphines, and Triarylphosphine Oxides. Substituent Effects on 15N, 31P, and 13C NMR Spectra
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The syntheses and 15N, 31P, and 13C NMR spectra of a series of N-phenyl-P,P,P-triarylphospha-λ5-azenes 4 and the 31P and 13C NMR spectra of the corresponding series of triarylphosphines 5 and triarylphosphine oxides 6 are reported.The substituent effects on the chemical shifts can be best accommodated and rationalized by use of a model for system 4 whereby the dipole of the aryl group and its pendant R group polarizes the rest of the molecule.This includes the P and N atoms and phenyl ring, where an electron-withdrawing R group increases the electron density of the P, N, and ipso C-1 while decreasing the electron density on C-3 and C-4 of the N-phenyl ring (Figure 3).A similar polarization pattern for the phosphine oxide series 6 is suggested.In the phosphine series 5, the chemical shift data is consistent with the lone electron pair on the phosphorus atom delocalizing into the aryl rings.The coupling constant data, in particular 1JPN for series 4 and 1JPC for series 4-6, were examined with use of the Hammett monosubstituent parameter (MSP) and the Taft dual-substituent parameter (DSP) approaches.For systems 4 and 6, without a lone electron pair on the phosphorus atom, a better electron-donating substituent increases the one-bond P-C(Ar) coupling constant.On the contrary, in the phosphine series 5, where there is a lone electron pair on the phosphorus, a better electron-withdrawing substituent increases the one-bond P-C(Ar) coupling constant.DSP treatment of 1JPC, and comparing to the few related systems in the literature,shows three types of systems.One, which includes 4 and 6, has an atom, phosphorus in these cases, that does not have a lone pair of electrons attached to the ring to which is attached an atom with a lone pair of electrons.Here, the resonance effect on 1JPC predominates.A second series, which includes phosphines 5, has a lone pair on the atom attached to the aryl ring.In these cases, the resonance effect is ca. 50percent greater than the inductive effect.Finally, the third series, exemplified by two examples from the literature, has a tetrahedral atom (without a lone pair) attached to the aryl ring and this in turn is attached to tetrahedral atoms without lone electron pairs.In these case, the resonance and inductive effects are fairly comparable.
- Chou, Whe-Narn,Pomerantz, Martin
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p. 2762 - 2769
(2007/10/02)
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- Syntheses and Spectroscopic Investigations of Substituted cis- and trans-Dichlorobis(triphenylphospane)platinum(II) Compounds
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Compounds of the type cis- and trans-dichlorobis(triphenylphosphane)platinum(II) (3) with substituents of different electronic character in the phenyl rings bonded to phosphorus have been synthesized.The coupling constants 1J and the chloro-platinum valence vibrational frequencies are demonstrated to be criteria for unambiguous discrimination between cis- and trans-configurations at platinum; a linear correlation exists between the sum of the ?-constants of the sustituents at the triphenylphosphane and the coupling constants 1J.
- Brune, Hans Albert,Falck, Manfred,Hemmer, Reinhard,Schmidtberg, Guenter,Alt, Helmut G.
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p. 2791 - 2802
(2007/10/02)
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