“Methyldiopium” and “methylbinapium”, chiral phosphoniumphosphine ligands

Leglaye, Pascale; Donnadieu, Bruno; Brunet, Jean‐Jacques; Chauvin, Rémi

doi:10.1016/s0040-4039(98)02138-8

Cited by 24 publications

(15 citation statements)

References 13 publications

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“…Several cationic binap derivatives bearing ammonium or phosphonium charges at the periphery have been proposed, [10] and in particular, binapium, [11] which is a monophosphane that could not enter the coordination sphere of cationic metals, [12] but which was made P,C-chelating by passing to the corresponding ylide. [13] Phosphonium ylides are actually phosphoniocarbyl ligands that can be regarded as reversed amidiniophosphane ligands.…”

Section: Introductionmentioning

confidence: 99%

An Atropo‐Stereogenic Diphosphane Ligand with a Proximal Cationic Charge: Specific Catalytic Properties of a Palladium Complex Thereof

et al. 2008

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A class of cationic diphosphane ligands combining phosphane and amidiniophosphane moieties is illustrated on the N‐methyl,N‐naphthylbenzimidazolium framework. The palladium(II) complex thereof is described and compared to the corresponding complex of the analogous neutral diphosphane. Contrary to first‐level expectations, the N2C–P and N2CP–Pd bonds in the cationic diphosphane complex are not longer than those occurring in its neutral counterpart. In the cationic ligand, the proximal positive charge is indeed conjugated to one phosphanyl group, and the coordination scheme is tentatively interpreted by resonance of the phosphane→metal dative bond (+N2C–P:→[Pd]) with a carbene→phosphenium dative bond (N2C:→[+P:→Pd]). Despite this peculiar structural feature, the electronic σ donation (vs. π acceptation) towards the palladium centre remains lowered in the cationic ligand. This specific property can be a priori valuable in a catalytic process where oxidative addition is not the limiting step. It is indeed shown that although the neutral complex is more active in Suzuki coupling reactions, the cationic complex is more active in Sonogashira‐type coupling reactions involving predissociated halide substrates, namely an acyl chloride. These likely atropo‐chiral ligands deserve to be resolved for application in asymmetric catalysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Section: Introductionmentioning

confidence: 99%

An Atropo‐Stereogenic Diphosphane Ligand with a Proximal Cationic Charge: Specific Catalytic Properties of a Palladium Complex Thereof

et al. 2008

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“…As a special feature of the 13 C CP/MAS spectra of X4 b and X4 d the signals of the ipso-C atoms are shifted to 122.5 and 121.9 ppm, respectively [26].…”

Section: Behavior Toward Ch 3 Imentioning

confidence: 93%

Accessibility and Solid State NMR Studies on Sol-Gel Processed Diphosphine Ligands

Lindner¹,

Brugger²,

Steinbrecher³

et al. 2001

Z. anorg. allg. Chem.

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Novel xerogels X1 a±d were obtained by sol-gel processing of the monomeric T-functionalized diphosphine ligand (MeO) 3 Si(CH 2 ) 6 CH[CH 2 PPh 2 ] 2 [1(T 0 )] with various amounts of the co-condensing agents MeSi(OMe) 2 -(CH 2 ) 6 (OMe) 2 SiMe (D 0 ±C 6 ±D 0 ) and MeSi(OMe) 2 (CH 2 ) 3 -(C 6 H 4 )(CH 2 ) 3 (OMe) 2 SiMe [Ph(1,4-C 3 D 0 ) 2 ]. 29 Si CP/MAS NMR spectroscopic investigations were applied to probe the matrices and their degree of condensation. The integrity of the hydrocarbon backbone and diphosphine moiety was examined by means of solid state NMR spectroscopy ( 13 C, 31 P). To study the dynamics of the matrices and the phosphorus centers detailed measurements of relaxation time (T 1qH ) and cross polarization constants (T SiH , T PH ) were carried out. The accessibility of the polysiloxane-supported diphosphines was scrutinized by some typical phosphine reactions. It was found that reagents such as H 2 O 2 , MeI as well as bulky molecules like (NBD)Mo(CO) 4 or (COD)PdCl 2 are able to reach all phosphorus centers independent on the kind of the backbone of the matrix. SEM micrographs show the morphology of the hybrid materials and energy dispersive X-ray spectroscopy (EDX) suggest that the distribution of the elements agree with the applied composition.

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“…The acidic aqueous fraction was basified to pH 8 with aq Na 2 CO 3 /NaHCO 3 , extracted with CH 2 Cl 2 (6 × 40 mL), dried (Na 2 SO 4 ), and concentrated in vacuo to give 6 (2.95 g, 6.91 mmol, 50%) as a yellow hygroscopic solid. 14 MeI (227 mg, 1.60 mmol) was added to (S)-BINAP (7; 1.00 g, 1.65 mmol) in CH 2 Cl 2 (20 mL). The reaction mixture was stirred for 16 h at 23°C.…”

Section: -(3-chlorophenyl)propan-1-ol (2k)mentioning

confidence: 99%

“…13 The reaction of (R)-BINAP (7) with one equivalent of MeI selectively afforded salt 8. 14 It was envisioned that these compounds might show a dual mode of activation. Based on our results we presumed the activation of the carbonyl group by the Lewis acidic phosphonium cation and the activation of the zinc reagent by the second functional group.…”

mentioning

confidence: 99%

Phosphonium Salt Catalyzed Addition of Diethylzinc to Aldehydes

Werner¹,

Riahi²,

Schramm³

2011

Synthesis

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The addition of diethylzinc to aromatic, heteroaromatic, and aliphatic aldehydes at room temperature is efficiently catalyzed by 1-7 mol% tetrabutylphosphonium chloride. The corresponding addition products are obtained in good to excellent yields of up to 99%. Moreover, polymer bond phosphonium salts can be used to catalyze this reaction with excellent recovery of the polymer bond catalyst up to three cycles. The application of chiral bifunctional phosphonium salts revealed a remarkable counter anion effect. Changing the anion, the activity of the tetrabutylphosphonium salt decreased in the order Cl -> Br -> I -≈ TsO -> BF 4 -≈ PF 6 -. However, the nature of the cation had also significant influence. Tetraalkylammonium chlorides showed similar activity compared to phosphonium chlorides, while alkaline metal chlorides proved to be considerably less active.

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“Methyldiopium” and “methylbinapium”, chiral phosphoniumphosphine ligands

Cited by 24 publications

References 13 publications

An Atropo‐Stereogenic Diphosphane Ligand with a Proximal Cationic Charge: Specific Catalytic Properties of a Palladium Complex Thereof

An Atropo‐Stereogenic Diphosphane Ligand with a Proximal Cationic Charge: Specific Catalytic Properties of a Palladium Complex Thereof

Accessibility and Solid State NMR Studies on Sol-Gel Processed Diphosphine Ligands

Phosphonium Salt Catalyzed Addition of Diethylzinc to Aldehydes

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