Phosphine ligands Bidentate

Transition metal complexes containing bidentate phosphine ligands. W. Levason and C. A. McAuliffe, Adv. Inorg. Chem. Radiochem., 1972,14,172-253 (315). 

Transition Metal Complexes Containing Bidentate Phosphine Ligands W. Levason and C. A. McAuliffe... 

When conducting hydrocarbonylations with dienes, it was found that a mixture of nonchelating and bidentate phosphine ligands was beneficial.241... 

More recently, Atwood et al. developed a platinum complex of a water-soluble, bidentate phosphine ligand, cA-(TPPTS)2PtCl2 [TPPTS = tris(sodium m -benzenesuI onatc)phosphi nc, as an effective hydration... 

Wender et al. reported a [5+2] cycloaddition in water by using a water-soluble rhodium catalyst having a bidentate phosphine ligand to give a 7-membered ring product (Eq. 4.69). This water-soluble catalyst was reused eight times without any significant loss in catalytic activity.133... 

The synthesis, characterization, and the relative thermodynamic hydricities of hydridoplatinum(II) species-containing bidentate phosphine ligands [PtHL2]+ (L2 = dppe, depe, dmpe, l,3-bis(dimethylphosphino)propane [dmpp]) have been determined, with the best hydride donor found to be [PtH(dmpe)2]+.365... 

Zinc telluride and zinc selenide polymetallic species with phosphine ligands have been structurally characterized 301 further details are discussed in Section 6.8.7. The use of mono- and bidentate phosphine ligands of varying steric bulk contributes to the variation of structural types in the formation of zinc tellurolate polyzinc species with Zn10, Zn14, and Zn16 species structurally characterized by Fenske et al.30... 

Complexation studies with bidentate phosphine ligands showed that stable cationic complexes of Tc(V), Tc(III), and Tc(I) are easily accessible. The influence of reaction conditions on reaction route and products is well demonstrated by the reaction of pertechnetate with the prototype 1,2-bis(dimethylphosphino)-ethane (dmpe) (Fig. 16). Careful control of reduction conditions allows the synthesis of [Tc02(dmpe)2]+, [TCl2(dmpe)2]+, and [Tc(dmpe)3]+, with the metal in the oxidation states V, III, and I [120,121]. This series illustrates the variety of oxidation states available to technetium and their successive generation by the action of a 2-electron reducing agent. 

Lin, J. J. (Texaco Development Corp.) Process for synthesis of amidoacids using a cobalt catalyst and a bidentate phosphine ligand Eur. Pat. Appl. 263,624 1988. Chem. Abstr. 1989, 110, 154881. 

A short five-step synthesis of a bifuran, namely ( )-2,2 -bis(diphenylphosphino)-3,3 -binaphtho[2,l-I>]furan (BINAPFu) from naphthofuranone via a low-valent titanium-mediated dimerization was reported. The newly developed resolution procedure for phosphines was utilized to provide the optically active bidentate phosphine ligands (BINAPFu), which consistently outperforms BINAP in the asymmetric Heck reaction between 2,3-dihydrofuran and phenyl triflate . Another way in which a benzofuranone can be converted into benzo[7 ]furan is by treatment of the former with 1-BU2AIH at -78°C followed by an acidic work up <00TL5803>. 

Chelating ligands have a much lower propensity for dissociation. Yet detailed kinetic studies on similar systems with bidentate phosphine ligands, /ac-(L2)PtMe3X (L2 = dppe (bis(diphenylphosphino)ethane), dppbz (bis(diphenylphosphinobenzene) X = I, OAc, OPh) also showed that ligand dissociation was required prior to any C-C coupling (48-51). In this case, however, the X- group rather than the phosphine was lost to form a five-coordinate intermediate, as shown in Scheme 11. A competitive C-X reductive elimination also occurs from these complexes and involves the same five-coordinate cation (Section V. A). 

Phosphoramidites are probably the most versatile ligands in this series as in amidites the substituents at the nitrogen atom are in close proximity to the metal centre and also the substituents could carry chiral centres. In Figure 4.22 we have depicted the simplest derivative, named Monophos , which is highly efficient for asymmetric hydrogenation but for a variety of other reactions as well. The ligand is much easier to make than most, if not all, chiral bidentate phosphine ligands and surely commercial applications will appear. 

The cross-dimerization of various electron-rich 1-alkynes 5 with electron-deficient internal alkynes such as methyl phenylpropiolate 6 was promoted by an [lrCl(cod)]2 combined with bidentate phosphine ligands such as (racj-BlNAP (Equation 10.2) [16]. This reaction produces a 1 1 adduct 7 in high regioselectivity and stereoselectivity. 

The application of a rhodium(I) catalyst bearing tunable bidentate phosphine ligands, such as 10, opened the possibility for the development of a new catalytic enantioselective reaction [13c]. In a control experiment, it was noted that the reaction with a catalyst containing a bidentate phosphine ligand, specifically RhCl(CO)(dppe), was significantly decelerated as compared to the reaction with [RhCl(CO)2]2 (Scheme 11.12). 

Following on the successful application of a rhodium(i) catalyst bearing tunable bidentate phosphine ligands such as 25, Jeong and co-workers reported a rhodium-based enantioselective PKR. ... 

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