- The importance of the Lewis base in lithium mediated metallation and bond cleavage reaction of allyl amines and allyl phosphines
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Metallation of two analogous N- and P-allyl molecules Ph2NCH2CHCH21 and Ph2PCH2CHCH22 with nBuLi have shown contrasting reactivities based on the choice of Lewis donor. With 1 metallation o
- Blair,Stevens,Thompson
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- Synthesis, Structure, and Solution Studies of Lithiated Allylic Phosphines and Phosphine Oxides
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This study reports a new series of 12 α-lithiated allylic phosphines and phosphine oxides. By incorporating Lewis base donors including diethyl ether (Et2O), tetrahydrofuran (THF), N,N,N′,N′,-tetramethylethylenediamine (TMEDA), and N,N,N′,N′,N″,-pentamethyldiethylenetriamine (PMDETA), nine complexes were structurally characterized by single-crystal X-ray crystallography. This includes novel dilithiated allylic phosphine 4 [PhP{CHCHCH2Li(TMEDA)}2] and a rare hemisolvated lithiated phosphine oxide 6 [{Ph2P(O)CHC(Me)CH2Li}2(TMEDA)]. Interestingly, in the solid state, P(III) complexes take advantage of Li-πinteractions to the newly formed delocalized system, in comparison to P(V) complexes where the oxophillic nature of the lithium atom dominates. All 12 complexes were fully characterized in the solution state by multinuclear NMR spectroscopy. DFT calculations on isomers of monomeric lithiated complex 3 [Ph2PCHC(Me)CH2Li(PMDETA)] described the low energy barrier between transition steps of the subtle delocalization of the allylic chain.
- Eren, Nimrod M.,Orr, Samantha A.,Thompson, Christopher D.,Border, Emily C.,Stevens, Michael A.,Blair, Victoria L.
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p. 2080 - 2090
(2020/06/05)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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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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- 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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- Structural importance of secondary interactions in molecules: Origin of unconventional conformations of phosphine-borane adducts
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The series of phosphine-borane adducts, Ph2(H 3C-C≡C)P-B(C6F5)3 (8c), Ph(H3C-C≡C)2P-B(C6F5) 3 (8b) and (H3C-C≡C)3P-B(C sub
- Spies, Patrick,Froehlich, Roland,Kehr, Gerald,Erker, Gerhard,Grimme, Stefan
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p. 333 - 343
(2008/09/18)
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- Phosphorus-carbon bond formation catalysed by electrophilic N-heterocyclic phosphines
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A P-chloro-diazaphospholene catalyses the phosphorus-carbon bond formation reaction between diphenylsilylphosphine and various alkyl chlorides. The Royal Society of Chemistry 2006.
- Burck, Sebastian,Foerster, Daniela,Gudat, Dietrich
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p. 2810 - 2812
(2008/09/19)
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- Concise syntheses of tridentate PNE ligands and their coordination chemistry with palladium(ii): A solution- and solid-state study
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A straightforward methodology for the high-yielding synthesis of the di-functionalised phosphines {Ph2P(CH2)2NC 4H8E, E = NMe (1), O (2), S (3)} via base-catalysed Michael addition is described. Reaction of the functionalised tertiary phosphines 1-3 with PdCl2(MeCN)2 affords complexes in which the ligands are bound in a tridentate fashion, namely [PdCl(κ 3-PNE)]Cl (6a, 8) as the predominant products. A κ2- PN coordination mode was also identified crystallographically for ligand 1 following its reaction with PdCl2(MeCN)2, which afforded [PdCl2(1-κ2-PN)] (6b) in ca. 5% yield. Conductivity studies of solutions of 6a are consistent with an ionic formulation, however the poor solubility of 7 and 8 precluded their study in a similar fashion. Analysis of bulk samples of [PdCl2(1)] (6) and [PdCl2(3)] (8) by 15N and 31P NMR spectroscopy in the solid state as consistent with exclusive tridentate binding of the PNE ligands. An X-ray crystallographic study has probed the coordination of 1 in the unusual salt [PdCl(1-κ3-PNN)]2[Mg(SO4) 2(OH2)4] (10) prepared by treating a methanolic solution of 6 with excess MgSO4. No data could be obtained to support the transformation of 6a into 6b on addition of excess chloride. In contrast, 6a reacts regioselectively with the water-soluble phosphine Cy 2PCH2CH2NMe3Cl to afford the cis-diphosphine complex cis-[PdCl(Cy2PCH2CH 2NMe3Cl)(1-κ2-PN)]Cl2 (9). Reaction of 1 with PdCl(Me)(COD) results in the formation of the κ2-PN dichloride complex [PdCl(Me)(1-κ2-PN)] (11). Attempts to prepare [Pd(Me)(MeCN)(1-κ2-PN)][PF 6] (12) through reaction of 11 with NaPF6 in MeCN led to decomposition. Treatment of PdMe2(TMEDA) with 1 at low temperature initially affords [PdMe2(1-κ2-NN)], which isomerises to afford [PdMe2(1-κ2-PN)] (13); at temperatures greater than 10 °C complex 13 decomposes rapidly. The Royal Society of Chemistry 2006.
- Anderson, Carly E.,Apperley, David C.,Batsanov, Andrei S.,Dyer, Philip W.,Howard, Judith A. K.
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p. 4134 - 4145
(2007/10/03)
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- Preparation of vinylphosphines by means of free radical addition of diphenylphosphine to alkynes and allenes
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Diphenylphosphine adds readily to alkynes and allenes under free radical conditions.Alkynes normally give E-vinylphosphines as the primary (kinetic) product, but Z-vinylphosphines are the main products isolated.Allenes generally give complex product mixtures in which the predominant components are vinyl phosphines formed via addition of the Ph2P. radical to the central carbon atom of the allene fragment.
- Mitchell, Terence N.,Heesche, Kerstin
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p. 163 - 170
(2007/10/02)
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- Addition of stannyl phosphines to alkynes and allenes
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Diphenyl(trimethylstannyl)phosphine adds to alkynes (both terminal and nonterminal) and allenes under free radical conditions.The former reaction occurs regiospecifically with preferential formation of E-isomers, the latter regioselectively.Product identi
- Mitchell, Terence N.,Belt, Heinz-Joachim
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p. 167 - 176
(2007/10/02)
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- FORMATION OF DIARYL(ALLYL)PHOSPHINE IN ?-ALLYL PALLADIUM(II) INDUCED CLEAVAGE OF TRIARYLPHOSPHINES
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A reverse migration of allylic group from palladium to phosphorus and the formation of diaryl(allyl)phosphine in the ?-allyl palladium(II) induced cleavage of triarylphosphines has been demonstrated.
- Goel, Anil B.
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p. 4599 - 4600
(2007/10/02)
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- SYNTHESIS AND REACTIVITY OF UNSATURATED BIPHOSPHONIUM SALTS
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The synthesis of 1,2 vinylene biphosphonium salts 1 has now benn enlarged to the vinylogous 1,4-butadienylene biphosphonium salts 2.The salts 2, a new class of unsaturated disalts, have also been prepared through a two-step isomerisation of acetylenic sal
- Cristau, Henri-Jean,Duc, Gerald,Labaudiniere, Lydie,Pietrasanta, Francine,Plenat, Francoise
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p. 113 - 116
(2007/10/02)
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- PHOSPHORORGANISCHE VERBINDUNGEN 90 Methodische Ausgestaltung der P-C und P-S-Cyanolyse am Beispiel einiger Heterophosphoniumsalze
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Treatment of allylamido-phosphonium salts with dry tetrabutylammonium cyanide in methylenechloride delivers after removal of the allyl group phosphinous acid amides with retention of configuration (P-C-cyanolysis).Allyl-O-alkylphosphonium salts undergo the Arbosov reaction under the above conditions, while allyl-S-alkyl phosphonium salts undergo fission of the P-S bond (P-S cyanolysis).Equally good results were obtained using KCN in methylene chloride accompained by catalytic amounts of 18-crown-6 ether; thus optically active benzyl-methyl-phenyl-phosphine-sulfid gave the corresponding phosphine with retention of configuration.Dithiophosphinic acid esters and thiophosphinic acid amides, after conversion to the corresponding quasiphosphonium salts via S-alkylation and subsequent treatment with tetrabutylammonium cyanide in methylenechloride, also give the corresponding thiophosphinous acid ester and phosphinous acid amide respectively.Thiophosphinic acid O-alkyl esters (R2P(S)OR') give however the thiophosphinic S-alkyl ester (R2P(O)SR') via an Arbusov reaction.The P-C cyanolysis of allyl-triphenylphosphoniumbromide using KCN/18-crown-6 or tetrabutylammonium cyanide in aprotic medium stops at the stage of the intermediary red-coloured ylide; addition of a proton-donor then results in the subsequent rearrangement to the corresponding propenyl-phosphonium salt.
- Horner, Leopold,Jordan, Manfred
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p. 215 - 220
(2007/10/02)
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