- Reactions of nitroxides, part 7: Synthesis of novel nitroxide selenoureas
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The reactions of 4-isoselenocyanato-2,2,6,6-tetramethylpiperidine-l-oxyl with selected amines and lower alcohols give the corresponding novel selenoureas and selenocarbamates, all bearing the nitroxyl moiety. Some of the synthesized selenoureas and seleno
- Zakrzewski, Jerzy,Krawczyk, Maria
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- Hydrogen/Halogen Exchange of Phosphines for the Rapid Formation of Cyclopolyphosphines
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The hydrogen/halogen exchange of phosphines has been exploited to establish a truly useable substrate scope and straightforward methodology for the formation of cyclopolyphosphines. Starting from a single dichlorophosphine, a sacrificial proton "donor phosphine"makes the rapid, mild synthesis of cyclopolyphosphines possible: reactions are complete within 10 min at room temperature. Novel (aryl)cyclopentaphosphines (ArP)5 have been formed in good conversion, with the crystal structures presented. The use of catalytic quantities of iron(III) acetylacetonate provides significant improvements in conversion in the context of diphosphine (Ar2P)2 and alkyl-substituted cyclotetra- or cyclopentaphosphine ((AlkylP)n, where n = 4 or 5) formation. Both iron-free and iron-mediated reactions show high levels of selectivity for one specific ring size. Finally, investigations into the reactivity of Fe(acac)3 suggest that the iron species is acting as a sink for the hydrochloric acid byproduct of the reaction.
- Barrett, Adam N.,Woof, Callum R.,Goult, Christopher A.,Gasperini, Danila,Mahon, Mary F.,Webster, Ruth L.
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supporting information
p. 16826 - 16833
(2021/11/04)
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- Phosphine-catalysed reductive coupling of dihalophosphanes
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Classically tetraaryl diphosphanes have been synthesized through Wurtz-type reductive coupling of halophosphanes R2PX or more recently, through the dehydrocoupling of phosphines R2PH. Catalytic variants of the dehydrocoupling reactio
- Hering-Junghans, Christian,Schumann, André,Siewert, Jan-Erik
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supporting information
p. 15111 - 15117
(2021/11/12)
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- Exploring the Reactivity of Donor-Stabilized Phosphenium Cations: Lewis Acid-Catalyzed Reduction of Chlorophosphanes by Silanes
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Phosphane-stabilized phosphenium cations react with silanes to effect either reduction to primary or secondary phosphanes, or formation of P-P bonded species depending upon counteranion. This operates for in situ generated phosphenium cations, allowing catalytic reduction of P(III)-Cl bonds in the absence of strong reducing agents. Anion and substituent dependence studies have allowed insight into the competing mechanisms involved.
- Pearce, Kyle G.,Borys, Andryj M.,Clark, Ewan R.,Shepherd, Helena J.
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p. 11530 - 11536
(2018/09/21)
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- Non-Metal-Catalyzed Heterodehydrocoupling of Phosphines and Hydrosilanes: Mechanistic Studies of B(C6F5)3-Mediated Formation of P-Si Bonds
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Non-metal-catalyzed heterodehydrocoupling of primary and secondary phosphines (R1R2PH, R2 = H or R1) with hydrosilanes (R3R4R5SiH, R4, R5 = H or R3) to produce synthetically useful silylphosphines (R1R2P-SiR3R4R5) has been achieved using B(C6F5)3 as the catalyst (10 mol %, 100 °C). Kinetic studies demonstrated that the reaction is first-order in hydrosilane and B(C6F5)3 but zero-order in phosphine. Control experiments, DFT calculations, and DOSY NMR studies suggest that a R1R2HP·B(C6F5)3 adduct is initially formed and undergoes partial dissociation to form an "encounter complex". The latter mediates frustrated Lewis pair type Si-H bond activation of the silane substrates. We also found that B(C6F5)3 catalyzes the homodehydrocoupling of primary phosphines to form cyclic phosphine rings and the first example of a non-metal-catalyzed hydrosilylation of P-P bonds to produce silylphosphines (R1R2P-SiR3R4R5). Moreover, the introduction of PhCN to the reactions involving secondary phosphines with hydrosilanes allowed the heterodehydrocoupling reaction to proceed efficiently under much milder conditions (1.0 mol % B(C6F5)3 at 25 °C). Mechanistic studies, as well as DFT calculations, revealed that PhCN plays a key mechanistic role in facilitating the dehydrocoupling reactions rather than simply functioning as H2-acceptor.
- Wu, Lipeng,Chitnis, Saurabh S.,Jiao, Haijun,Annibale, Vincent T.,Manners, Ian
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supporting information
p. 16780 - 16790
(2017/11/28)
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- Facile Phenylphosphinidene Transfer Reactions from Carbene–Phosphinidene Zinc Complexes
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Phosphinidenes [R-P] are convenient P1 building blocks for the synthesis of a plethora of organophosphorus compounds. Thus far, transition-metal-complexed phosphinidenes have been used for their singlet ground-state reactivity to promote selective addition and insertion reactions. One disadvantage of this approach is that after transfer of the P1 moiety to the substrate, a challenging demetallation step is required to provide the free phosphine. We report a simple method that enables the Lewis acid promoted transfer of phenylphosphinidene, [PhP], from NHC=PPh adducts (NHC=N-heterocyclic carbene) to various substrates to produce directly uncoordinated phosphorus heterocycles that are difficult to obtain otherwise.
- Krachko, Tetiana,Bispinghoff, Mark,Tondreau, Aaron M.,Stein, Daniel,Baker, Matthew,Ehlers, Andreas W.,Slootweg, J. Chris,Grützmacher, Hansj?rg
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supporting information
p. 7948 - 7951
(2017/06/27)
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- Selectivity effects in zirconium-catalyzed heterodehydrocoupling reactions of phosphines
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Zirconium compounds are known to dehydrocouple phosphines catalytically. An exploration of the factors that may promote selective heterodehydrocoupling was performed, revealing that steric factors are important but do not provide substantial selectivity. It was observed that 5-(Me3SiNCH2CH2)2N(CH2CH2NSiMe2CH2)Zr (1) may be sufficiently Lewis acidic to perform Lewis acid or frustrated Lewis pair catalysis.
- Ghebreab, Michael B.,Costanza, Sierra,Waterman, Rory
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p. 668 - 670
(2016/04/20)
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- Cationic 5-phosphonio-substituted N-heterocyclic carbenes
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2-Phosphanyl-substituted imidazolium salts 2-PR2(4,5-Cl-Im)[OTf] (9a,b[OTf]) (4,5-Cl-Im = 4,5-dichloro-1,3-bis(2,6-di-isopropylphenyl)-imidazolium) (a: R = Cy, b: R = Ph) are prepared from the reaction of R2PCl (R = Cy, Ph) with NHC 8 (4,5-dichloro-1,3-bis(2,6-di-isopropylphenyl)-imidazolin-2-ylidene) in the presence of Me3SiOTf. 5-Phospanyl-substituted imidazolium salts 5-PR2(2,4-Cl-Im)[OTf] (10a,b[OTf]) are obtained in quantitative yield when a slight excess of the NHC 8 is used. 5-Phosphonio-substituted imidazolium salts 5-PR2Me(2,4-Cl-Im)[OTf]2 (14a,b[OTf]2) and 5-PR2F(2,4-Cl-Im)[OTf]2 (16a,b[OTf]2) result from methylation reaction or oxidation of 10a,b[OTf] with XeF2 and subsequent fluoride abstraction. According to our quantum chemical studies the Cl1 atom at the 2-position at the imidazolium ring of dication 14b2+ carries a slightly positive charge and is therefore accessible for nucleophilic attack. Accordingly, the reaction of 14a,b[OTf]2 and 16a,b[OTf]2 with R3P (R = Cy, Ph) affords cationic 5-phosphonio-substituted NHCs 5-PR2Me(4-Cl-NHC)[OTf] (17a,b[OTf]) and 5-PR2F(4-Cl-NHC)[OTf] (18a,b[OTf]) via a SN2(Cl)-type reaction. A series of transition metal complexes such as [AuCl(5-PPh2Me(4-Cl-NHC))][OTf] (19[OTf]), [CuBr(5-PPh2Me(4-Cl-NHC))][OTf] (20[OTf]), [AuCl(5-PPh2F(4-Cl-NHC))[OTf] (21[OTf]) and [RhCl(cod)(5-PPh2Me(4-Cl-NHC))][OTf] (23[OTf]) are prepared to prove the coordination abilities of carbenes 17b[OTf] and 18b[OTf]. The isolation of a rare example of a tricationic bis-carbene silver complex [Ag(5-PPh2Me(4-Cl-NHC))2][OTf]3 (22[OTf]3) is achieved by reacting 14b[OTf] with Cy3P in the presence of AgOTf. NHC 17b[OTf] represents a very effective dehydrocoupling reagent for secondary (R2PH, R = Ph, Cy, iBu) and primary (RPH2, R = Ph, Cy) phosphanes to give diphosphanes of type R4P2 (R = Ph, Cy, iBu) and oligophosphanes R4P4, R5P5 (R = Ph, Cy), respectively. Methylation of 17b+ and subsequent deprotonation reaction with LDA affords the cationic NHO (N-heterocyclic olefin) 35+ of which the gold complex 36+ is readily accessible via the reaction with AuCl(tht).
- Schwedtmann, Kai,Schoemaker, Robin,Hennersdorf, Felix,Bauzá, Antonio,Frontera, Antonio,Weiss, Robert,Weigand, Jan J.
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supporting information
p. 11384 - 11396
(2016/07/26)
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- Metal-free Lewis acid mediated dehydrocoupling of phosphines and concurrent hydrogenation
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The stoichiometric reaction of trityl cation with two equivalents of Ph2PH affords the phosphine stabilized phosphenium salt [Ph2(H)PPPh2][B(C6F5)4] via hydride abstraction, while catalytic amounts of B(p-HC6F4)3 effects catalytic phosphine dehydrocoupling with the liberation of H2. This reaction is accelerated by the presence of olefin or imine, effecting concurrent hydrogenation.
- Dobrovetsky, Roman,Takeuchi, Katsuhiko,Stephan, Douglas W.
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p. 2396 - 2398
(2015/02/05)
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- 1,2-Phosphaborines: Hybrid Inorganic/Organic P-B Analogues of Benzene
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Photolysis of the cyclic phosphine oligomer [PPh]5 in the presence of pentaarylboroles leads to the formation of 1,2-phosphaborines by the formal insertion of a phenylphosphinidene fragment into the endocyclic C-B bond. The solid-state structur
- Barnard, Jonathan H.,Brown, Paul A.,Shuford, Kevin L.,Martin, Caleb D.
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supporting information
p. 12083 - 12086
(2015/10/12)
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- The reductive P-P coupling of primary and secondary phosphines mediated by N-heterocyclic carbenes
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The dehydrogenative coupling of primary and secondary phosphines with the N-heterocyclic carbene iPr2Im (1,3-di-isopropyl-imidazolin-2-ylidene) has been reported. The dehydrogenation of R2PH affords diphosphines R2P-PRsub
- Schneider, Heidi,Schmidt, David,Radius, Udo
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p. 10138 - 10141
(2015/06/22)
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- Facile, Catalytic Dehydrocoupling of Phosphines Using β-Diketiminate Iron(II) Complexes
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Catalytic dehydrocoupling of primary and secondary phosphines has been achieved for the first time using an iron pre-catalyst. The reaction proceeds under mild reaction conditions and is successful with a range of diarylphosphines. A proton acceptor is not needed for the transformation to take place, but addition of 1-hexene does allow for turnover at 50°C. The catalytic system developed also facilitates the dehydrocoupling of phenylphosphane and dicyclohexylphosphane. A change in solvent switches off dehydrocoupling to allow hydrophosphination of alkenes.
- King, Andrew K.,Buchard, Antoine,Mahon, Mary F.,Webster, Ruth L.
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supporting information
p. 15960 - 15963
(2015/11/03)
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- Selective dehydrocoupling of phosphines by lithium chloride carbenoids
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The development of a simple, transition-metal-free approach for the formation of phosphorus-phosphorus bonds through dehydrocoupling of phosphines is presented. The reaction is mediated by electronically stabilized lithium chloride carbenoids and affords a variety of different diphosphines under mild reaction conditions. The developed protocol is simple and highly efficient and allows the isolation of novel functionalized diphosphines in high yields.
- Molitor, Sebastian,Becker, Julia,Gessner, Viktoria H.
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supporting information
p. 15517 - 15520
(2014/12/12)
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- A simple straightforward synthesis of phenylphosphane and the photoinitiator bis(mesitoyl)phenylphosphane oxide (IRGACURE 819)
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A straightforward high-yield synthesis for the photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphane oxide (16, IRGACURE 819) involves: i) the reaction of phenyldichlorophosphane, PhPCl2, with sodium to give [Na2(P2Ph2)(tmeda)]6 (5); ii) protonation of 5 with tert-butanol to give 1,2-diphenyldiphosphane, PhHP-PHPh (12); iii) reduction of 12 by sodium to yield [Na(PHPh)x (13); iv) protonation of 13 with tert-butanol to give phenylphosphane PhPH2 (14) in excellent yields; v) reaction of 14 with 2,4,6-trimethylbenzoylchloride (MesCOCI) in presence of the NaOt-Bu formed in steps ii and iv to give bis(2,4,6-trimethylbenzoyl)phenylphosphane 7; vi) oxygenation of 7 with 30% aqueous hydrogen peroxide to give the final product 16. This reaction can be performed in toluene with about 4 vol-% of tmeda as an activator in a one-pot synthesis without changing the solvent. The structures determined by X-ray diffraction of the unique hexameric aggregate 5 and 16 are reported. Schweizerische Chemische Gesellschaft.
- Gruetzmacher, Hansjoerg,Geier, Jens,Stein, Daniel,Ott, Timo,Schoenberg, Hartmut,Sommerlade, Reinhard H.,Boulmaaz, Souad,Wolf, Jean-Pierre,Murer, Peter,Ulrich, Thomas
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- PROCESS FOR PREPARING ACYLPHOSPHANES AND THEIR OXIDES AND SULPHIDES
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A process for the preparation of bis-acylphosphanes of formula R1P(COR2)2 wherein R1 is unsubstituted phenyl or phenyl substituted by one to five halogen, C1-C8-alkyl, C1-C8-alkylthio and/or C1-C8-alkoxy; R2 is C1-C18-alkyl or C2-C18-alkenyl ; C1C18-alkyl or C2-C18-alkenyl substituted once or more than once by halogen -OR10, -OCO-R10, -OCO-Hal, -COO-R10, -N(R11)-CO-R10, -N(R11)-CO-Hal, -CO-NR11R10, -CH=CH-CO-OR10 or -CH=CH-phenyl; -C(C1-C4alkyl)=C(C1-C4alkyl)-CO-OR10 or -C(C1-C4alkyl)=C(C1-C4alkyl)-phenyl; C5-C12cycloalkyl, C2-C18alkenyl, phenyl-C1-C4alkyl, phenyl, naphthyl, biphenyl or a 5- or 6-membered -0-, S- or N-containing heterocyclic ring, the radicals phenyl, naphthyl, biphenyl or the 5- or 6-membered -0-, S- or N-containing heterocyclic ring being unsubstituted or substituted by one to five halogen, C1-C8alkyl, C1-C8alkoxy and/or C1-C8alkylthio; the process comprises the steps in a) selective reduction of dichlorophenylphosphanes of the formula R1P(CI)2 by means of hydrogen at a temperature in the range from 20 to 200°C and under hydrogen pressure of atmospheric pressure to 20bar in the presence of a hydrogenation catalyst, a tert. aliphatic amine or an aromatic amine and in the presence of a non protic solvent which is unreactive under the hydrogenation conditions to obtain cyclic phenylphosphanes (R1P)n (n = 4 to 6); or b) selective reduction of R1P(CI)2 by means of hydrogen at a temperature in the range from 80 to 25O°C and under hydrogen pressure of 25 to 250bar in the presence of a hydrogenation catalyst, a tert. aliphatic amine or an aromatic amine and in the presence of a non protic solvent which is unreactive under the hydrogenation conditions to obtain R1PH2; c) subsequent reaction with an acid halide of formula in the presence of an apropriate base R2COHal wherein R2 is as defined above.
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Page/Page column 9
(2008/06/13)
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- Catalytic P-H activation by Ti and Zr catalysts
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Catalytic dehydrocoupling of phosphines was investigated using the anionic zirconocene trihydride salts [Cp*2Zr(μ-H) 3Li]3 (1a) or [Cp*2Zr(μ H) 3K(thf)4] (1b), and the metallocycles [CpTi(NPtBu 3)(CH2)4] (6) and [Cp*M(NPtBu 3)(CH2)4] (M = Ti 20, Zr 21) as catalyst precursors. Dehydrocoupling of primary phosphines RPH2 (R = Ph, C6H2Me3, Cy, C10H7) gave both dehydrocoupled dimers RP(H)P(H)R or cyclic oligophosphines (RP)n (n = 4, 5) while reaction of tBu3C6H2PH 2 gave the phosphaindoline fBu2(Me2C-CH 2)C6H2PH (9). Stoichiometric reactions of these catalyst precursors withprimary phosphines afforded [Cp* 2Zr((PR)2)H][K(thf)4] (R = Ph 2, Cy 3, C 6H2Me3 4), [Cp*2Zr((PPh) 3)H] [K(thf)4] (5), [CpTi(NPtBu3)(PPh) 3] (7) and [CpTi(NPfBu3)(nrPHPh)]2 (8), while reaction of 6 with (C6H2tBu3)PH2 in the presence of PMe3 afforded [CpTi(NPtBu3)(PMe 3)(P(C6H2tBu3)] (10). The secondary phosphines Ph2PH and (PhHPCH2)2CH2 also undergo dehydrocoupling affording (Ph2P)2 and (PhPCH2)2CH2. The bisphosphines (CH 2PH2)2 and C6H4(PH 2)2 are dehydrocoupled to give (PCH2CH 2PH)v (12) and (C6H4P(PH)) 2 (13) while prolonged reaction of 13 gave (C6H 4P2)8 (14). The analogous bisphosphine Me 2C6H4(PH)2 (17) was prepared and dehydrocoupling catalysis afforded (Me2C6H 2P(PH))2 (18) and subsequently [(Me2C 6H2P2)2(μ-Me2C 6H2P2)]2 (19). Stoichiometric reactions with these bi-sphosphines gave [Cp*2Zr(H)(PH)2C 6H4][Li(thf)4] (22), [CpTi(NPtBu 3)(PH)2C6H4]2 (23) and [Cp*Ti(NPfBu3)(PH)2C6H4] (24). Mechanistic implications are discussed.
- Masuda, Jason D.,Hoskin, Aaron J.,Graham, Todd W.,Beddie, Chad,Fermin, Maria C.,Etkin, Nola,Stephan, Douglas W.
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p. 8696 - 8707
(2007/10/03)
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- PROCESS FOR PREPARING ACYLPHOSPHANES AND DERIVATIVES THEREOF
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The present invention relates to a new, selective process for the preparation of mono- and bisacylphosphanes of formula (I) n and m are each independently of the other 1 or 2; R1, if n = 1, is e.g. phenyl R1, if n = 2, is e.g. C1-C18alkylene or phenylene; R2 is e. g. C1-C18alkyl, phenyl or substituted phenyl; R3 is e. g. C1-C18alkyl, by (1) reacting a phosphorous halide of formula Ila or a phosphorous halide oxide of formula (Ilb) or a phosphorous halide sulfide of formula (IIc) with an alkali metal in a solvent in the presence of a proton source; (2) subsequent reaction with m acid halides of formula (III) An oxidation step may follow to obtain mono- and bisacylphosphane oxides or mono-and bisacylphosphane sulfides.
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Page/Page column 39-40
(2010/02/10)
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- Electrocatalytic eco-efficient functionalization of white phosphorus
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The novel eco-efficient methods to transform white phosphorus into the esters of phosphoric, phosphorous and phosphonic acids, tertiary phosphines and other organophosphorus compounds under conditions of electrochemical catalysis were elaborated. The mechanism of these processes was investigated using the method of cyclic voltammetry and preparative electrolysis.
- Budnikova, Yulia H.,Yakhvarov, Dmitry G.,Sinyashin, Oleg G.
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p. 2416 - 2425
(2007/10/03)
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- New reactions of selenocarboxylates
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(Chemical Equation Presented) By treatment with Woollins' reagent in toluene solution, carboxylic acids are converted to selenocarboxylic acids. The latter react in situ to provide new products of acid- or base-promoted substitution, addition, and amidation.
- Knapp, Spencer,Darout, Etzer
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p. 203 - 206
(2007/10/03)
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- A new synthesis of (PhPSe2)2 (woollins reagent) and its use in the synthesis of novel P-Se heterocycles
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A new and improved method for the preparation of (PhPSe2) 2 (Woollins reagent (WR), 1) is reported. Reaction of dichlorophenylphosphine with Na2Se, (prepared from the reaction of elemental selenium and sodium in liquid ammonia) gives WR with excellent purity, high yield and on a larger scale than was previously possible. Four novel phosphorus-selenium heterocycles, including a spirocyclic heterocycle exhibiting a four-membered P2SeC ring, were obtained from the reaction of WR with two reactive substrates (diphenylcyclopropenone and methyl phenylpropiolate). Useful selenocarbonyl and thiocarbonyl compounds were obtained from the reaction of both WR and Lawesson's reagent with diphenylcyclopropenone. All new compounds were characterised spectroscopically and three demonstrative X-ray structures are reported.
- Gray, Ian P.,Bhattacharyya, Pravat,Slawin, Alexandra M. Z.,Woollins, J. Derek
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p. 6221 - 6227
(2007/10/03)
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- PROCESS FOR THE SYNTHESIS OF CYCLOORGANYLPHOSPHANES AND DI(ALKALI METAL/ALKALINE EARTH METAL) OLIGOPHOSPHANEDIIDES
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The invention relates to a process for the preparation of cycloorganylphosphanes of formula 1(R1P)n by reaction of dihalo(organyl)phosphanes of formula R1PHal2 with: a) activated zinc in an organic solvent, or w
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- The influence of the sacrificial anode nature on the mechanism of electrochemical arylation and alkylation of white phosphorus
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The material of the sacrificial anode has a substantial effect on the nature and yield of the target products of electrochemical phosphorylation of organic halides by white phosphorus in the presence of the nickel complexes with 2,2′-bipyridine. The use of the zinc anode results in the products with tricoordinated phosphorus, viz., triorganylphosphines, the reaction on the aluminum anode affords triorganylphosphine oxides, and the presence of Mg 2+ ions in the reaction mixture provides the transformation of white phosphorus into cyclic phosphines (PhP)5.
- Yakhvarov,Budnikova,Tazeev,Sinyashin
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p. 2059 - 2064
(2007/10/03)
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- Coordination Catalysis in Organic Electrosynthesis. Electrochemical Phosphorylation of Organic Halides in the Presence of Samarium Dichloride
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The feasibility was demonstrated for arylation (or alkylation) of white phosphorus under the action of electrochemically generated Sm(II).
- Budnikova,Yakhvarov,Kargin
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p. 566 - 569
(2007/10/03)
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- Ylidylphosphanes and -diphosphanes
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Chlorophosphanyl and dichlorophosphanyl alkylidene- and benzylidenephosphoranes 6 and 8 are converted by reaction with LiAlH4 to the respective phosphanes 7 and 9. The former can be isolated, but decompose on heating or on protonation to give the ylidyl diphosphane 11 and the phosphonium ylide or phosphonium salt, respectively. The final products are the cyclooligophosphanes 15-17. Only the C-tert-butyl derivative 7c is stable in both regards. The conformation of the RPH group in 7 as compared to that of the RPCl group in 6 clearly reflects their different interaction with the ylide moiety.
- Breitsameter, Florian,Schmidpeter, Alfred,Schier, Annette
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p. 381 - 388
(2007/10/03)
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- Nouveaux complexes a enchainement Ge-Ru-Ge: les bis(dimethylgermyl)alcane ruthenium tetracarbonyles. I. Synthese et reactions de clivage
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Bis(dimethylgermyl)alkane ruthenium tetracarbonyls (n = 1, 2) are obtained by reaction of bis(dimethylgermyl)alkanes Me2(H)Ge(CH2)nGe(H)Me2 (n = 1, 2) with Ru3(CO)12 under UV irradiation, or by heating.Various CO substitution reactions with phosphines by heating and cleavage reactions with protonic, electrophilic, nucleophilic or radical reagents are described.X-O oxides (X = Hg, C5H5N, C6H5N, Me2S) are deoxidized by these complexes.
- Barrau, Jacques,Hamida, Najib Ben,Satge, Jacques
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- Organosubstituted 2,5-Dihydro-1,2,5-phosphasilaboroles - Preparation, Characterization, and Transformations
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The dimeric 4,5-diethyl-2,5-dihydro-2,2-dimethyl-3-organo-1-phenyl-1,2,5-phosphasilaboroles are prepared in yields of 70-80percent from the acylic (Z)-2-boryl-1-silylethene derivatives ClB(C2H5)C(C2H5)=CRSi(CH3)2Cl with Li2PC6H5.The solid (1a)2 is the trans isomer with a (PB)2 ring (X-ray analysis). (1a)2 forms the solid γ-Pic-1a with γ-picoline (γ-Pic), with trimethylphosphane (TMP) the easily dissociating TMP-1a. trans-Bis(4,5-diethyl-1,2,5,6-tetrahydro-2,2,3-trimethyl-1-phenyl-1,2,5-phosphasilaborin) (2a)2 (X-ray analysis) is obtained by methylene migration from (1a)2 and methylenetriphenylphosphorane (MTPP). (1a)2 reacts with trimethylamine N-oxide (TMANO) by C6H5P/O-exchange to form (3a) and (3'a), whereas (1a)2 and γ-picoline N-oxide (PNO) give γ-Pic-3a and (C6H5P)n (4; 4', 4'': n = 4-6). (1a)2 and electrophiles react to 1:1 addition compounds (1a-AlCl3; 1a-MeI).The crystalline (5a)2 is prepared by B/Al exchange from (1a)2 and 2. (1a)2 reacts with methanol by ring opening to give the (Z)-2-boryl-1-silylethene derivative CH3OB(C2H5)C(C2H5)=C(CH3)Si(CH3)2OCH3 (6a) and phenylphosphane (7) in high yield. (1a)2 and acetylacetone undergo C6H5P/O exchange giving a mixture of 3a and (Z/E)-4-(phenylphosphino)-3-penten-2-one (8). - The 11B-, 13C-, 29Si-, 31P-NMR data of the dimeric C2SiPB and C2SiPCB rings are compared and discussed together with the data of the unsaturated C2SiElB rings .
- Koester, Roland,Seidel, Guenter,Mueller, Gerhard,Boese, Roland,Wrackmeyer, Bernd
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p. 1381 - 1392
(2007/10/02)
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- Organosubstituted 2,5-Dihydro-1,2,5-selenasilaboroles - Preparation, Characterization, and ?-Complexation
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The dichloro compounds ClB(C2H5)CC2H5=C(R)Si(CH3)2Cl : R = CH3; B: R = C(CH3)=CH2> react with Na2Se to form the five-membered cyclic compounds .A and Na2Se2 yield 1a and 3 (2). 1a is also formed from and Se in addition to (C6H5P)n and (C6H5P)4Se (5). - (3a)2 reacts with S8 to give the compounds (7a), (4)n (n = 4,5), and (C6H5P)4S (6). - 1a reacts with CH3OH under elimination of H2Se to form the intramolecularly associated (8).From 1a and acetylacetone (9) and C5H7O2B(C2H5)SeSi(CH3)2C(CH3)=CH(C2H5) (10) are obtained. 1 : 1 Adducts are synthesised from 1a or b with Lewis acids (1a-AlCl3, 1b-AlCl3) and with Lewis bases (Py-1a, Py-1b, TMP-1a). - 1a and b react thermally or photochemically with (ligand)transition metal(0) compounds or with (ligand)transition metal(I) compounds to form η4-?-complexes 4-1a, (OC)3Ru-η4-1a, Ni(η4-1a)2 (X-ray structure analysis), C5H5Co-η4-1a, (OC)3Fe-η4-1b, (OC)3Ru-η4-1b, Ni(η4-1b)2, C5H5Co-η4-1b>.The MS and NMR data (1H, 11B, 13C, 29Si, 77Se) of the new compounds are compared with those of other C2SiElB ring compounds (El = O, S, N, P).
- Koester, Roland,Seidel, Guenter,Boese, Roland,Wrackmeyer, Bernd
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p. 1955 - 1966
(2007/10/02)
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- Linear Oligophosphaalkanes, XIX. - Partial Alkylation of Phenylphosphane with Dihalomethanes CH2X2 (X = Cl, Br) - A Facile Synthesis of Methylenebis(phenylphosphane), HPhP-CH2-PPhH
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The reaction of PhPHNa with CH2X2 (X = Cl, Br) in tetrahydrofuran affords methylenebis(phenylphosphane), HPhP-CH2-PPhH (2), phenylphosphane, methylphenylphosphane, PhPHMe, and 1,2,3,4-tetraphenylcyclo-5-carba-1,2,3,4-tetraphosphane, CH2(PPh)4 (3).HPhP-CH2-PPhH (2) may be obtained in a facile one-step synthesis with yields up to 70percent by reaction of PhPH2 with CH2Cl2 and KOH in dimethyl sulfoxide/H2O or dimethylformamide/H2O.The formation of PhPHMe and CH2-(PPh4)4 may be explained by a reaction scheme including P-phenylphosphaalkene PhP=CH2 and HPhP-CH2Cl as reactive intermediates.The reactions between PhPHM (M = Na, K) and CH2Cl2 or CH2Br2 respectively, have been studied by independent experiments.
- Langhans, Klaus P.,Stelzer, Othmar
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p. 1707 - 1712
(2007/10/02)
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- PH-Functional Phosphanes with 2-Pyridyl Substituents in α- or β-Position 2-C5H4N-n-PRH (R = H, iPr, tBu, Ph, 2-C5H4N-n; n = 1, 2)
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PH-functional phosphanes containing a 2-pyridyl substituent in α- or β-position to phosphorus, e.g. 2-C5H4N-n-PRH (R = H, iPr, tBu, Ph; n = 1, 2) have been obtained.The reactivity of the PH-groups can be employed for the synthesis of tridentate NPN-hybrid donors, 2PR (R = H, Ph).The phosphanes 2-C5H4N-n-PRH behave as monodentate ligands in transition metal complexes and form labile chelate ring systems.They may bridge metal-metal bonds to form seven membered ring systems, e.g.Mo2PC3N.The coordination of the N-donor of the ligands 2-C5H4N- n-PRH to a transition metal atom is indicated by a lowfield shift and a small (31)P-(13)C-splitting of the 13C NMR signal of carbon atom 6 in the pyridin ring system. - 2-Pyridyl Substituent, Reactions at PH-Functions, Chelate Complexes, Ligand Replacement, 13C NMR Spectra
- Spiegel, Gerd U.,Stelzer, Othmar
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p. 579 - 588
(2007/10/02)
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- A new general route to diphosphenes via germylated compounds
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Several (trichlorogermyl)phosphines RP(H)GeCl3 (3) are prepared by two different routes: (i) from primary phosphines RPH2 and germanium tetrachloride and (ii) from dichlorophosphines RPCl2 and the dichlorogermylene-dioxane complex, GeCl2·C4H8O2. Subsequent addition of 3 to an excess of DBU (1,5-diazabicyclo [5.4.0] undec-5-ene) affords the corresponding diphosphenes RP=PR. This method appears conveniently and generally applicable to the synthesis of diphosphenes. This reaction involves formation of chlorophosphine intermediates RP(H)Cl (2). Stable diphosphenes 1c, bis(2,4,6-tri-tert-butylphenyl)-diphosphene, and 1e, bis[bis(trimethylsilyl)methyl]diphosphene, can be isolated in excellent yield. Unstable dienophilic diphosphenes were characterized by cycloaddition with 1,3-dienes. Cycloadduct 12d, obtained by reaction of di-tert-butyldiphosphene with cyclopentadiene, is a clean precursor of di-tert-butyldiphosphene, 1d.
- Couret, Claude,Escudie, Jean,Ranaivonjatovo, Henri,Satgé, Jacques
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p. 113 - 117
(2008/10/08)
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- Degradation of (PhP)5 by Cyanide: Formation, Structure, and Reactions of the Phenyl Cyanophosphide Ion
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Phenyl cyanophosphide PhPCN- is formed in the ractions of P(CN)2- with phenyllithium and of PhP(CN)2 with CN-, and it may be prepared by nucleophilic degradation of (PhP)5 with ammonium or phosphonium cyanides.With sulfur it yields phenyl cyanodithiophosphinates 4, by alkylation alkyl(phenyl)cyanophosphanes 6 and by hydrolysis of the latter alkyl(phenyl)phosphine oxides 7. - The molecular structure of PhPCN (3c) as determined by X-ray analysis shows an almost planar anion with 102 deg CPC angle.A long PC and short CN bond in the PCN group make PhPCN- appear as "cyanide complex of phenylphosphinidene".
- Schmidpeter, Alfred,Zirzow, Karl-Heinz,Burget, Guenther,Huttner, Gottfried,Jibril, Ibrahim
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p. 1695 - 1706
(2007/10/02)
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- On Organophosphorus Compounds, XXII. 1,2-Diaryl-1,2-dibromodiphosphanes
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1,2-Diaryl-1,2-dibromodiphosphanes R(Br)P-P(Br)R 2 (R = C6H5; 4-XC6H4, X = CH3O, F, Cl) were prepared by dehalogenation of RPBr2 with magnesium in a one-batch procedure.While solid 2 presumably consists of only one diastereomer there exists an equilibrium between meso-2, rac-2 and their disproportionation products RPBr2 and (RP)5 in solutions of 2.The influence of temperature, R and solvent on this equilibrium was investigated. - The reaction products of the dissolved phenyl compound 2a correspond to a reaction of its disproportionation products PhPBr2 and (PhP)5, the former preferably reacting on nucleophilic substitution, the latter with electrophilic agents.Under heterogenous conditions diphosphanes Ph(R)P-P(R)Ph can be obtained from 2a and LiR.
- Hinke, Axel,Kuchen, Wilhelm
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p. 3003 - 3010
(2007/10/02)
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- PHOTOCHEMICAL REACTIONS OF PHOSPHAALKENES
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Photolysis of phosphaalkenes leads to an inversion of polarity of the phosphorus carbon double bond and to a cleavage into transient phosphinidene and carbene; unexpected alcoholysis of a PIII-C bond and the cycloaddition of a linear phosphaalkene on a diene are also reported.
- Meriem, Abdelkader,Majoral, Jean-Pierre,Revel, Monique,Navech, Jacques
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p. 1975 - 1978
(2007/10/02)
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- Cyclodiop, an example of a new class of chiral diphosphines
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Cyclodiop, a chiral diphosphine with an intact PP bond was prepared and used as a ligand in rhodium complexes. Asynunetric reduction of some prochiral olefins was observed. The nature of the rhodium complexes is discussed in the light of their P nmr spectra.
- Zhang,Yemul,Kagan,Stern,Commereuc,Chauvin
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p. 3955 - 3958
(2007/10/02)
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- BEITRAEGE ZUR CHEMIE DES PHOSPHORS 90. 1,2,3-TRIPHENYLTRIPHOSPHAN
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The title compound 1 is formed as the main product of alcoholysis of 1,2,3-triphenyl-1,3-bis(trimethylsilyl)-triphosphane, (Me3Si)2(PPh)3.The triphosphane is relatively stable in solution below -30 grad C.At room temperature, 1 disproportionates yielding PhPH2, H2(PPh)2 and (PPh)5.These rearrangements take place via a four-membered transition state preferentially involving P-P bonds.In solution 1 forms the three diastereomers 1a(threo/threo), 1b(threo/erythro), and 1c(erythro/erythro) in a ratio of about 3:4:1.Their correlation to the 31P NMR spectroscopically observed spin systems results from the dependence of the 1JP-P-coupling constants on dihedral angles and from the ratio of the isomers immediately after the stereospecific solvolysis.
- Baudler, M.,Reuschenbach, G.
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