Triphénylphosphine | EPFL Graph Search

La triphénylphosphine ou le triphénylphosphane (IUPAC), est un composé organophosphoré de formule P(C6H5)3 - parfois abrégé en PPh3 ou Ph3P. Elle est largement utilisée dans la synthèse de composés organiques et organométalliques. C'est un composé relativement stable qui existe sous la forme d'un solide cristallin à température ambiante et qui se dissout dans les solvants non polaires comme le benzène. Préparation La triphénylphosphine peut être préparée en laboratoire par traitement du trichlorure de phosphore avec le bromure de phénylmagnésium ou le phényllithium. La synthèse industrielle met en jeu la réaction de Friedel-Crafts entre le trichlorure de phosphore et le benzène. La triphénylphosphine peut être recristallisée soit dans l'éthanol chaud soit dans l'isopropanol chaud. Cette purification est parfois conseillée pour enlever l'oxyde de triphénylphosphine, de formule OP(C6H5)3, qui s'est formé par oxydation lente par l'air. Principales réactions organiq

New Synthetic Applications of Water Acetate Pd/TPPTS Catalyst Generated in situ. Evidence for true Pd(0) Valent Species Intermediate

Christian Amatore

Studies on the sp-sp intermolecular coupling reactions with the palladium water-soluble catalyst prepared in situ from palladium(II) acetate and sulfonated triphenylphosphine P(C6H4-m-SO3Na)(3) (TPPTS) in a homogeneous acetonitrile-water system, without Cu(I) promotor, afford diynes with moderate yields (45-65%). Under the same conditions, the sp(2)-sp coupling of 2-iodophenols or 2-iodoanilines and terminal alkynes followed by intramolecular cyclization gives indolic and furanic products in good yields (60-99%). Under these aqueous conditions, an efficient and short synthesis of eutypine illustrated the synthetic potentiality of the coupling. Furthermore, through a series of kinetic and P-31 NMR experiments, we have demonstrated that a mixture of Pd(OAc)(2) and TPPTS affords spontaneously a palladium(0) complex, through formation of bivalent complex Pd(OAc)(2)-(TPPTS)(2). A detailed mechanism of the reaction has been investigated thoroughly and the pertinent rate constants measured. The resulting palladium(0) complex reacts with phenyl iodide via an oxidative addition. This complex is considerably less reactive than the corresponding complex generated from PPh(3), probably due to steric effects.

1995

Ligand synthesis for homogeneous catalysis

Michael Maurin

Organophosphorus compounds found applications in varied fields of the organic chemistry: they are particularly present in natural compounds such as the deoxyribonucleic acid (DNA) and in the field of catalysis in which their utility is also proven. Thus, this thesis work first focused on the preparation of various phosphorus ligands utilizable in transition metal catalysed reactions. Being given the importance of this type of reaction in organic synthesis, it appears essential to have many ligands at disposal in order to fine-tune and to optimize the reaction conditions as much as possible. Thus, the first objective of this work was to propose a simple and general method for the preparation of monodentate phosphorus ligands. Based on the use of phosphites in substitution for the usual phosphorus trihalides, this method was initially tested during the preparation of different simple triarylphosphines. Thereafter, this method was extended to the synthesis of new ligands having more complex structures. The yields obtained for the latter as well as the variety of the substrates authorized by this method confirmed its value and suggested its application to the synthesis of new heteroaromatic phosphines. The preparation of bidentate phosphorus ligands based on chiral biphenyl motifs was then addressed. For that purpose, the 2,2',6,6' -tetrabromobiphenyl was chosen as a pivot substrate for the development of a modular synthetic approach. Indeed, by means of successive halogen/metal permutational exchanges and after treatment with the suitable electrophile, it was possible to functionalize this substrate, isolate each atropisomer in enantiomerically pure form, and finally convert each one of those into chiral biphenylbisphosphines. In addition, it was also possible, during the synthesis of these ligands, to evaluate the rotational stability of some enantiomerically pure dilithiobiphenyls by means of dynamic nuclear magnetic resonance experiments.

EPFL2007

Hydrogen Production by Selective Dehydrogenation of HCOOH Catalyzed by Ru-Biaryl Sulfonated Phosphines in Aqueous Solution

Gabor Laurenczy, Katerina Stefania Sordakis

The selective dehydrogenation of aqueous solutions of HCOOH/HCOONa to H2 and CO2 gas mixtures has been investigated using RuCl3·3H2O as a homogeneous catalyst precursor in the presence of di␣erent monoaryl-biaryl or alkyl-biaryl phosphines and aryl diphosphines bearing sulfonated groups. All catalytic systems were used in water without any additives and proved to be active at 90 °C, giving high conversions and good TOF values. As an alternative Ru(II) metal precursor, the known dimer [Ru( 6-C6H6)Cl2]2 was also tested as in situ catalyst with selected phosphines as well as an isolated Ru(II)-catalyst with one of them. By using high-pressure NMR (HPNMR) techniques, indications on the nature of the active species involved in the catalytic cycles were obtained.

American Chemical Society2014

Ligand synthesis for homogeneous catalysis

Michael Maurin

EPFL2007