- Diastereoselective Rhodium Catalyzed [4 + 2] Cycloisomerization of Allenes
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A diastereoselective [4 + 2] cycloisomerization of asymmetric allenyl dienes is reported. The asymmetric dienyl allenes are synthesized using the method reported by Ma. These substrates readily undergo diastereoselective intramolecular rhodium catalyzed [4 + 2] cycloisomerization analogous to thermal intramolecular Diels-Alder reactions. Overall, 29 examples are presented with tethers possessing nitrogen, oxygen, and carbon. Diastereoselectivities range from 99:1 to 90:10 in most examples.
- Li, Jun,Gilbertson, Scott R.
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supporting information
p. 2911 - 2914
(2021/05/05)
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- 31P NMR spectroscopic analysis on photooxidation of 1,n-bis(diphenylphosphino)alkanes with the aid of DFT calculations
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The chloroform-d solution of diphosphine, 1,n-bis(diphenylphosphino)alkane (Ph2P(CH2)nPPh2; n = 1-6), was photolyzed with light from a xenon lamp in air. The progress of the reaction was followed by 31P NMR spectroscopy. The observed spectral change showed that the diphosphine is initially oxidized to diphosphine monoxide, Ph2P(═O)(CH2)nPPh2, which is further oxidized to diphosphine dioxide, Ph2P(═O)(CH2)nP(═O)Ph2. The oxidation of the diphosphine to the diphosphine monoxide took place according to first-order kinetics with respect to the concentration of the diphosphine, the first-order rate constant, kobs, being larger with increasing number of the methylene units in the spacer. The observation in kinetics is interpreted based on the conformation of the diphosphine radical cation intermediate initially generated by electron transfer from the photoexcited diphosphine to oxygen. Density functional theory (DFT) calculations predict that the diphosphine radical cation takes “folded” conformation where two phosphorus atoms are arranged closely to each other. The “folded” conformer of the diphosphine radical cation results from electrostatic interaction of these two phosphorus atoms. This conformer explains the observed dependency of kobs on the length of the spacer in the diphosphine.
- Yasui, Shinro,Yamazaki, Shoko
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- Rearrangement and redistribution reaction of Ph2PCH2TMS with PhAsCl2 or AsCl3
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The attempted synthesis of bis(diphenylphosphinomethyl) phenylarsane and tris(diphenylphosphinomethyl) arsane through condensation of chloro arsanes and diphenyl (trimethylsilylmethyl) phosphane yielded a number of side products originating from migratory and redox-reactions in addition to the targeted ligands. An unexpected, 1,3,4-phosphadiarssolan-1-ium salt was obtained and crystallographically characterized as an A-shaped chlorido adduct.
- Gupta, Arvind Kumar,Green, Joshua P.,Orthaber, Andreas
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p. 967 - 971
(2019/07/03)
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- Zero-Valent Amino-Olefin Cobalt Complexes as Catalysts for Oxygen Atom Transfer Reactions from Nitrous Oxide
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The synthesis and characterization of several zero-valent cobalt complexes with a bis(olefin)-amino ligand is presented. Some of these complexes proved to be efficient catalysts for the selective oxidation of secondary and allylic phosphanes, as well as diphosphanes, even with a direct P?P bond. With 5 mol % catalyst loadings the oxidations proceed under mild conditions (25–70 °C, 7–22 h, 2 bar N2O) and afford good to excellent yields (65–98 %). In this process, the greenhouse gas N2O is catalytically converted into benign N2and added-value organophosphorus compounds, some of which are difficult to obtain otherwise.
- Gianetti, Thomas L.,Rodríguez-Lugo, Rafael E.,Harmer, Jeffrey R.,Trincado, Monica,Vogt, Matthias,Santiso-Quinones, Gustavo,Grützmacher, Hansj?rg
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supporting information
p. 15323 - 15328
(2016/12/06)
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- Intramolecular stabilization of the phosphine radical cation by the second phosphorus atom during the photooxidation of diphosphines:31P NMR spectroscopic analysis
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Diphosphines, Ph2P(CH2)nPPh2 1 (n = 1, 2, 3, 4, and 6), were photolyzed by a xenon lamp in air. The 31P NMR spectroscopic analysis of the reaction showed that 1 is oxidized, according to first-order kinetics, to the monoxide, which is further oxidized to the dioxide. The dependence of the rate constants for the first oxidation on the chain-length n in 1 is interpreted in terms of the orientation of the p-orbitals on the two phosphorus atoms in the intermediate, the diphosphine radical cation.
- Yasui, Shinro,Yamazaki, Shoko
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p. 422 - 424
(2015/05/27)
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- Synthesis of phosphorus(V)-stabilized geminal dianions. the cases of mixed P=X/PBH3 (X = S, O) and P=S/SiMe3 derivatives
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The monodeprotonation of [CH2(PPh2BH 3)(PPh2=E)] (E = S (6), O (7)) afforded [CH(PPh 2BH3)(PPh2=E)]- (E = S (6 -), O (7-)), whose structures were confirmed by X-ray crystallography. The kinetics of the second deprotonation appeared to be crucial in efficient synthesis of the corresponding dianions. Thus, the double deprotonation of 6 only led to 62-; the analogous reaction with 7 was slower and resulted only in the partial formation of 72-. Double deprotonation of the compound [CH2(SiMe3)(PPh 2=S)] (8) also resulted in the partial formation of [C(SiMe 3)(PPh2=S)]2- (82-), whose structure was confirmed by X-ray crystallography. The rare monomeric Mg carbene compound [MgC(PPh2BH3)(PPh2=S)] (9) was obtained by the reaction of 6 with Mg(nBu)2. The X-ray structure of 9 is presented.
- Heuclin, Hadrien,Fustier-Boutignon, Marie,Ho, Samuel Ying-Fu,Goff, Xavier-Frederic Le,Carenco, Sophie,So, Cheuk-Wai,Mezailles, Nicolas
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p. 498 - 508
(2013/03/14)
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- Selective mono reduction of bis-phosphine oxides under mild conditions
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Bis-phosphine oxides can be selectively reduced to bis-phosphine monoxides under exceptionally mild conditions using triflic anhydride and a thiol. The Royal Society of Chemistry.
- Petersson, Maria J.,Loughlin, Wendy A.,Jenkins, Ian D.
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experimental part
p. 4493 - 4494
(2009/05/06)
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- A novel mild deprotection method for phosphine-boranes
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Treatment of phosphine-boranes with molecular sieves 4A in a mixture of an ethereal solvent and an alcohol provided deprotected free phosphines in quantitative yields. The phosphines can be obtained by a simple filtration/crystallization procedure in most cases. It should be noted that the current method is successfully applied to the deprotection of a phosphite-borane for the first time.
- Schroeder, Marc,Nozaki, Kyoko,Hiyama, Tamejiro
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p. 1931 - 1932
(2007/10/03)
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- A practical synthesis of the first P-phosphinoylmethyl-λ5-phosphazenes
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The new N-aryl-P,P-diphenyl-P-(diphenylphosphinoyl)methyl-λ5-phosphazenes 2 have been prepared by three different approaches starting from the commercially available bis(diphenylphosphino)methane. Either oxidation of the mono-λ5-phosphazenes 3 or imination of the monoxide 4 yielded compounds 2 in moderate yields. The third method involved deprotonation of the easily accesible aminophosphonium salts 5.
- Alajarin,Lopez-Leonardo,Llamas-Lorente,Bautista
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p. 2085 - 2091
(2007/10/03)
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- Facile and general synthesis of polyphosphane polyoxides with (O)PCP(O) linkages
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Polyphosphane polyoxides with (O)PCP(O) linkages are powerful chelating agents for extraction of actinides from nuclear wastes. They are obtained either by the Michaelis-Arbuzov reaction of chloromethylphosphane oxides and phosphorus(III) esters, or by the reaction of phosphane oxide carbanions with chlorophosphanes. With the latter method, the addition of a phosphane oxide carbanion in excess allowed us to overcome a transmetallation reaction and thereby obtain polyphosphane polyoxides in good yields. The 1H-NMR spectra of the PCH2P groups show the influence of the different R groups attached to the phosphorus atoms. We determined the coupling constants and the chemical shifts of these spin systems.
- Cristau, Henri-Jean,Virieux, David,Mouchet, Patrick,Fruchier, Alain
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p. 1561 - 1569
(2007/10/03)
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- Organometallic chemistry of the lanthanides: 1H and 31P NMR studies of the coordination of bifunctional ligands OPPh2CH(R)PPh2 to neodymium derivatives. Access to heterobimetallic complexes.
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Neodymium compounds give rise to stable adducts upon treatment with phosphine oxides. 31P NMR is found to be of special interest for the study of such paramagnetic complexes.The bifunctional ligands OPPh2CH(R)PPh2 are used to build heterobimetallics.Key Words: heterobimetallics / neodymium / bifunctional ligand: phosphine-phosphine oxide / 31P NMR
- Visseaux, M.,Dormond, A.,Baudry, D.
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p. 173 - 184
(2007/10/02)
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- New method for synthesis of methylenebis(diarylphosphine) monoxides
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Synthesis of methylenebis(diphenyl- and methylenebis(di-p-tolylphosphine) monoxides, via the reaction of diarylphosphines with formic acid in presence of concentrated hydrochloric acid is described. Methylenebis(diphenylphosphine) monoxide is oxidized with hydrogen peroxide and sulfur into the corresponding methylenebis(diphenylphosphine) dioxide and methylenebis(diphenylphosphine) monoxide monosulfide. Attempts to carry out this reaction with butylphenyl- and dibutylphosphines failed.
- Bondarenko,Rudomino,Tsvetkov
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p. 125 - 126
(2007/10/02)
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- The Crystal Structure of Me3SiNPPh2CH2PPh2 and NMR Investigations on its Proposed Thermal Isomerization
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The crystal structure of Me3SiNPPh2CH2PPh2 (1) has been determined in order to obtain information about the ground state conformation in the solid, and about unusual steric effects which could give rise to conformational isomers.It was recently proposed t
- Schmidbaur, Hubert,Bowmaker, Graham A.,Kumberger, Otto,Mueller, Gerhard,Wolfsberger, Werner
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p. 476 - 482
(2007/10/02)
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- COMPLEXES OF PLATINUM(II) AND PALLADIUM(II) WITH HYBRID PHOSPHINE-PHOSPHINE OXIDE LIGANDS OF TYPE Ph2P(CH2)nP(=O)Ph2 (n=1,2,3, OR 4)
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Treatment of t)2> or with Ph2P(CH2)nP(=O)Ph2 (n=1, dppmO; n=2, dppeO; n=3, dpppO; n=4, dppbO) gives complexes of the type cis-2>, independently of mole ratio.Treatment of cis- with LiBr or NaI gives (X=Br, cis; X=I, cis/trans mixture) and on treatment with Hg(CCPh)2 in ethanol, trans-CPh)2(dppmO)2> is formed.Treatment of these ligands with gives exclusively cis-2>.Coordination of the P=O group was achieved by treating 2> with either AgNO3 or TlPF6, whereupon cis-2>(2+) (n=1, or 2) is formed: these cations were also synthesized by treating O)Ph2>2> with HBF4.Treatment of with dppmO gives trans- only and this reacts with AgNO3 or TlPF6 to form cis-(2+).The complexes were characterized by microanalysis, IR and NMR spectroscopy.
- Higgins, Simon J.,Taylor, Richard,Shaw, Bernard L.
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p. 285 - 292
(2007/10/02)
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- Unsymmetrical bis-phosphorus ligands. VII. Metal complexes with diphenylphosphinodiphenylphosphorylalkanes
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The syntheses of some mixed phosphine-phosphine oxide ligands, Ph2P(O)CHRPPh2 (R = H, CH3, n-Pr), are described. Some phosphonium salts and chelate coordination compounds with mercury and cadmium halides and chromium, moly
- Grim, Samuel O.,Satek, Larry C.,Tolman, Chadwick A.,Jesson
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p. 656 - 660
(2007/10/06)
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