18899-64-4Relevant articles and documents
Mechanism of phosphorus-carbon bond cleavage by lithium in tertiary phosphines. An optimized synthesis of 1,2-bis(phenylphosphino)ethane
Dogan, John,Schulte, Jurgen B.,Swiegers, Gerhard F.,Wild, S. Bruce
, p. 951 - 957 (2000)
Conditions influencing the extent of P-C(aryl) vs P-C(alkyl) bond cleavage in the reaction of Ph2P(CH2)2PPh2 with lithium in THF have been investigated. The results complement and elucidate earlier work; they indicate that the mechanism of P-C bond cleavage in tertiary phosphines of this type involves a thermodynamic equilibrium between P-C(aryl) and P- C(alkyl) cleaved radicals and anions, followed by reaction and stabilization of these as lithium salts. The addition of water to the reaction mixture causes a reestablishment of the cleavage equilibrium prior to the formation of the secondary phosphines. A mechanism involving competitive release of leaving groups as the thermodynamically most stable anion or radical has been proposed. The preparation of (R*, R*)-(±)/(R*, S*)-PhP(H)(CH2)2P(H)Ph by this route has been optimized.
The synthesis and characterisation of bis(phenylpyridylphosphino)ethane
Butler, Ian R.,Licence, Peter,Coles, Simon J.,Hursthouse, Michael B.
, p. 103 - 107 (2000)
A novel synthesis has been devised for the preparation of unsymmetrical phosphine substituted derivatives of bis(diphenylphosphino)ethane [dppe]. The title ligand has been prepared in a two step procedure from dppe. A palladium(II) complex of this new ligand has been prepared and characterised by single crystal X-ray diffraction.
Zirconium-Catalyzed Intermolecular Double Hydrophosphination of Alkynes with a Primary Phosphine
Bange, Christine A.,Waterman, Rory
, p. 6413 - 6416 (2016)
Catalytic double hydrophosphination of internal alkynes and primary phosphines is possible using a zirconium complex, [κ5-N,N,N,N,C-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH]Zr (1). The reaction proceeds via stepwise hydrophosphination to give vinyl phosphine products, which can be isolated or further converted to the respective 1,2-bis(phosphino)ethane (i.e., double hydrophosphination). The catalysis is highly selective for formation of secondary phosphine products.
Contrasting protonation behavior of diphosphido vs dithiolato diiron(I) carbonyl complexes
Zaffaroni, Riccardo,Rauchfuss, Thomas B.,Fuller, Amy,De Gioia, Luca,Zampella, Giuseppe
, p. 232 - 238 (2013/02/25)
This paper reports on the protonation of phosphine-substituted diiron diphosphido carbonyls, analogues of diiron dithiolato centers at the active sites of hydrogenase enzymes. Reaction of the diphosphines (CH2) n(PPhH)2 (n = 2 (edpH2) and n = 3 (pdpH 2)) with Fe3(CO)12 gave excellent yields of Fe2(edp)(CO)6 (1) and Fe2(pdp)(CO)6 (2). Substitution of Fe2(edp)(CO)6 with PMe3 afforded Fe2(edp)(CO)2(PMe3)4 (3; νCO 1855 and 1836 cm-1). Crystallographic analysis showed that 3 adopts an idealized C2 symmetry, with pairs of phosphine ligands occupying apical-basal sites on each Fe center. Relative to that in the dithiolato complex, the Fe-Fe bond (2.7786(8) A) is elongated by 0.15 A. Treatment of 3 with H(OEt2)2BAr F4 (ArF = C6H3-3,5- (CF3)2) gave exclusively the C2-symmetric μ-hydride complex [HFe2(edp)(CO)2(PMe3) 4]+. This result contrasts with the behavior of the analogous ethanedithiolate Fe2(edt)(CO)2(PMe 3)4 (edt = 1,2-C2H4S2), protonation of which gives both the bridging and terminal hydride complexes. This difference points to the participation of the sulfur centers in the formation of terminal hydrides. The absence of terminal hydride intermediates was also revealed in the protonation of the diphosphine diphosphido complexes Fe2(pdp)(CO)4(dppv) (4; dppv = cis-1,2-C2H 2(PPh2)2) and Fe2(edp)(CO) 4(dppbz) (5; dppbz = 1,2-C6H4(PPh 2)2). Protonation of these diphosphine complexes afforded μ-hydrido cations with apical-basal diphosphine ligands, which convert to the isomer where the diphosphine is dibasal. In contrast, protonation of the dithiolato complex Fe2(pdt)(CO)4(dppv) gave terminal hydrides, which isomerize to μ-hydrides. In a competition experiment, 4 was shown to protonate faster than Fe2(pdt)(CO)4(dppv).
1,3,6-azadiphosphacycloheptanes: A novel type of heterocyclic diphosphines
Karasik, Andrey A.,Balueva, Anna S.,Moussina, Elvira I.,Naumov, Roman N.,Dobrynin, Alexey B.,Krivolapov, Dmitry B.,Litvinov, Igor A.,Sinyashin, Oleg G.
, p. 125 - 132 (2008/09/18)
The novel type of seven-membered cyclic diphosphines, namely 1,3,6-azadiphosphacycloheptanes, has been synthesized by condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde, and primary amines (aniline, p-toluidine, benzylamine, and 5-aminoisophthalic acid) as a mixture of rac-and meso-stereoisomers. The structures of rac-stereo-isomers of N-tolyl and N-(3′,5′-dicarboxyphenyl)-substituted diphosphines were investigated by X-ray crystal structure analyses. The stereoisomers of N-(3′,5′- dicarboxyphenyl)-substituted compound were separated at a preparative scale, and their platinum(II) dichloride complexes were obtained. The corresponding meso-isomer readily forms P,P-chelate complex with [PtCl2(cod)], whereas the rac-stereoisomer forms oligomeric complex.
Syntheses of new chiral phosphane ligands by diastereoselective conjugate addition of phosphides to enantiomerically pure acceptor-substituted olefins from the chiral pool
Wiese, Burkhard,Knuehl, Guido,Flubacher, Dietmar,Priess, Jan W.,Ulriksen, Bolette,Broedner, Kerstin,Helmchen, Guenter
, p. 3246 - 3262 (2007/10/03)
A variety of new chiral phosphanes were prepared by highly diastereoselective additions of phosphanes to α,β-unsaturated carbonyl compounds and related acceptor-substituted olefins derived from myrtenal as ex chiral pool source. Monophosphanes with astereogenic as well as stereogenic phosphorus are described. In addition diphosphanes were prepared by a highly diastereoselective double conjugate addition of a secondary diphosphane. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
