1605-53-4Relevant academic research and scientific papers
Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities
Stevens, Michael A.,Hashim, Fairuz H.,Gwee, Eunice S. H.,Izgorodina, Ekaterina I.,Mulvey, Robert E.,Blair, Victoria L.
, p. 15669 - 15677 (2018/09/27)
A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2SiMe3)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2PCH3Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6H4PiPr2)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6H4NEt2)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6H5)}2] 5 and [(TMEDA)Na2(TMP)(C6H5PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C?H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.
Reduction of phosphine oxides to the corresponding phosphine derivatives in Mg/Me3SiCl/DMI system
Kuroboshi, Manabu,Kita, Toshihito,Aono, Asuka,Katagiri, Toshimasa,Kikuchi, Seiya,Yamane, Syoko,Kawakubo, Hiromu,Tanaka, Hideo
, p. 918 - 920 (2015/02/05)
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.
Part I: The development of the catalytic wittig reaction
O'Brien, Christopher J.,Nixon, Zachary S.,Holohan, Andrew J.,Kunkel, Stephen R.,Tellez, Jennifer L.,Doonan, Bryan J.,Coyle, Emma E.,Lavigne, Florie,Kang, Lauren J.,Przeworski, Katherine C.
supporting information, p. 15281 - 15289 (2013/11/06)
We have developed the first catalytic (in phosphane) Wittig reaction (CWR). The utilization of an organosilane was pivotal for success as it allowed for the chemoselective reduction of a phosphane oxide. Protocol optimization evaluated the phosphane oxide precatalyst structure, loading, organosilane, temperature, solvent, and base. These studies demonstrated that to maintain viable catalytic performance it was necessary to employ cyclic phosphane oxide precatalysts of type 1. Initial substrate studies utilized sodium carbonate as a base, and further experimentation identified N,N-diisopropylethylamine (DIPEA) as a soluble alternative. The use of DIPEA improved the ease of use, broadened the substrate scope, and decreased the precatalyst loading. The optimized protocols were compatible with alkyl, aryl, and heterocyclic (furyl, indolyl, pyridyl, pyrrolyl, and thienyl) aldehydes to produce both di- and trisubstituted olefins in moderate-to-high yields (60-96 %) by using a precatalyst loading of 4-10 mol %. Kinetic E/Z selectivity was generally 66:34; complete E selectivity for disubstituted α,β-unsaturated products was achieved through a phosphane-mediated isomerization event. The CWR was applied to the synthesis of 54, a known precursor to the anti-Alzheimer drug donepezil hydrochloride, on a multigram scale (12.2 g, 74 % yield). In addition, to our knowledge, the described CWR is the only transition-/heavy-metal-free catalytic olefination process, excluding proton-catalyzed elimination reactions. A point of difference: By utilizing an organosilane to chemoselectively reduce a phosphane oxide precatalyst to a phosphane (see scheme), the first catalytic (in phosphane) Wittig reaction has been developed. The methodology has been applied to the synthesis of 22 disubstituted and 24 trisubstituted olefins, including a multigram synthesis of a precursor to the anti-Alzheimer drug donepezil hydrochloride.
General and selective copper-catalyzed reduction of tertiary and secondary phosphine oxides: Convenient synthesis of phosphines
Li, Yuehui,Das, Shoubhik,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
supporting information; experimental part, p. 9727 - 9732 (2012/07/14)
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.
An acidity scale for phosphorus-containing compounds including metal hydrides and dihydrogen complexes in THF: Toward the unification of acidity scales
Abdur-Rashid, Kamaluddin,Fong, Tina P.,Greaves, Bronwyn,Gusev, Dmitry G.,Hinman, Justin G.,Landau, Shaun E.,Lough, Alan J.,Morris, Robert H.
, p. 9155 - 9171 (2007/10/03)
More than 70 equilibrium constants K between acids and bases, mainly phosphine derivatives, have been measured in tetrahydrofuran (THF) at 20 °C by 1H and/or 31P NMR. The acids were chosen or newly synthesized in order to cover the wide pK(α)(THF) range of 5-41 versus the anchor compound [HPCy3]BPh4 at 9.7. These pK(α)(THF) values are approximations to absolute, free ion pK(a)(THF) and are obtained by crudely correcting the observed K for 1:1 ion-pairing effects by use of the Fuoss equation. The acid/base compounds include 14 phosphonium/phosphine couples, 17 cationic hydride/neutral hydride couples, 9 neutral polyhydride/anionic hydride couples, 14 dihydrogen/hydride couples, and 4 other nitrogen- and phosphorus-based acids. The effects on pK(α) of the counterions BAr'4- and BF4- vs BPh4- and [K(2,2,2-crypt)]+ versus [K(18-crown-6)+ are found to be minor after correcting for differences in inter-ion distances in the ion-pairs involved. Correlations with v(M-H) noted here for the first time suggest that destabilization of M-H bonding in the conjugate base hydride is an important contributor to hydride acidity. It appears that Re-H bonding in the anions [ReH6(PR3)2- is greatly weakened by small increases in the basicity of PR3, resulting in a large increase in the pK(α) of the conjugate acid ReH7(PR3)2. Correlations with other scales allow an estimate of the pK(α)(THF) values of more than 1000 inorganic and organic acids, 20 carbonyl hydride complexes, 46 cationic hydrides complexes, and dihydrogen gas. Therefore, many new acid-base reactions can be predicted and known reactions explained. THF, with its low dielectric constant, disfavors the ionization of neutral acids HA over HB+ and therefore separate lines are found for pK(α)(THF)(HA) and pK(α)(THF)(HB+) when plotted against pK(a)(DMSO) or pK(a)(MeCN). The crystal structure of [Re(H)2(PMe3)5]BPh4 is reported.
Kinetic Studies on the Reaction of Triethyl- and Diethylphenyl-phosphine with Carbon Disulphide in Nitrile Solutions
Campino, Trinidad,Santos, Jose G.,Ibanez, Fernando
, p. 1021 - 1024 (2007/10/02)
The kinetics of the reactions of carbon disulphide with triethylphosphine and diethylphenylphosphine are studied in solutions of acetonitrile, propionitrile, isobutyronitrile, benzonitrile, benzyl cyanide, and some of their mixtures.The reaction shows reversible pseudo-first-order kinetics. Activation and equilibrium parameters are discussed in terms of solvent properties.
A Simple Synthesis and Some Synthetic Applications of Substituted Phosphide and Phosphinite Anions
Tsvetkov, E. N.,Bondarenko, N. A.,Malakhova, I. G.,Kabachnik, M. I.
, p. 198 - 208 (2007/10/02)
Based on data for the acidity relationship of phosphines and phosphinous acids and water in dimethyl sulfoxide and water, a simple method is reported for the generation of phosphide and phosphinite anions by the action of concentrated aqueous alkali on primary and secondary phosphines as well as phosphinous acids in dimethyl sulfoxide or other dipolar aprotic solvents.Alkylation of the anion yields secondary and tertiary phosphines, polyphosphines, functionally substituted phosphines as well as similarly substituted phosphine oxides.Phosphinous acids have beenalkylated in various solvents in two-phase systems containing concentrated aqueous alkali and tetrabutylammonium iodide as phase transfer catalyst.
OPTISCH AKTIVE PHOSPHINE DURCH ASYMMETRISCHE SUBSTITUTION PROCHIRALER, HOMOCHIRAL SUBSTITUIERTER PHOSPHONITE
Neuffer, J.,Richter, W. J.
, p. 289 - 298 (2007/10/02)
Phenylphosphonous acid dimenthylester and its dibornylester react with bulky nucleophiles to give diastereomeric phosphinous acid esters.The asymmetric induction is as high as 95 percent d.e.If reaction conditions favouring inversion at phosphorus are used then the (R)-menthoxy group of the prochiral starting material is substituted.The phosphinous acid ester can be converted, with partial racemization, into optically active Horner-phosphines.
Notes Unsymmetrical Bis(phosphorus) Compounds: Synthesis of Unsymmetrical Ditertiary Phosphines, Phosphine Oxides, and Diquaternary Phosphonium Salts
Benn, Roger F.,Briggs, Josie C.,McAuliffe, Charles A.
, p. 293 - 296 (2007/10/02)
A convenient preparative route to the unsymmetrical bidentate phosphines R2P(CH2)nPPh2 (R=Me or Et; n=3 or 4) is described.This involves the synthesis of unsymmetrical diphosphonium salts, Br2, and diphosphine oxides, R2P(O)(CH2)nPPh2, as intermediates.The symmetrical ligand Et2P(CH2)3PEt2 was also prepared by the same route.New co-ordination complexes of manganese(II) with these ligands have been isolated.
