Search results for "Phosphane"
showing 9 items of 79 documents
Base-assisted synthesis of 4-pyridinate gold(I) metallaligands: a study of their use in self-assembly reactions
2021
Made available in DSpace on 2021-06-25T12:16:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-06 Ministerio de Economia y Competitividad (MINECO/FEDER) of Spain Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The synthesis of di- and tritopic gold(I) metallaligands of the type [(Au4-py)(2)(mu(2)-diphosphane)] (diphosphane = bis(diphenylphosphanyl)isopropane or dppip (1), 1,2-bis(diphenylphosphanyl)ethane or dppe (2), 1,3-bis(diphenylphosphanyl)propane or dppp (3) and 1,4-bis(diphenylphosphanyl)butane or dppb (4)) and [(Au4-py)(3)(mu(3)-triphosphane)] (triphosphane = 1,1,1-tris(diphenylphosph…
A Versatile Palladium/Triphosphane System for Direct Arylation of Heteroarenes with Chloroarenes at Low Catalyst Loading
2010
International audience; Put a ring on it: The use of an air-stable, robust palladium/tridentate phosphane catalyst in direct C[BOND]H and C[BOND]Cl activation reactions is reported (see scheme; DMAc=N,N-dimethylacetamide, TBAB=tetra-n-butylammonium bromide). Electron-rich, electron-poor, and polysubstituted furans (X=O), thiophenes (X=S), pyrroles (X=NR5), and thiazoles were arylated with chloroarenes in the presence of the catalyst.
The first catalytic method for Heck alkynylation of unactivated aryl bromides (copper-free Sonogashira) in an ionic liquid: 1 mol-percent palladium/t…
2007
Herein we report the studies of Heck alkynylation (copper-free Sonogashira) with aryl halides (I, Br, Cl) employing various metallic precursors, tertiary phosphanes and bases in [BMIM][BF4] as the solvent. As a result, we provide the first method that allows the coupling of a large array of substrates, either activated or deactivated bromides in an ionic liquid. Furthermore, the system of highest efficiency is unexpectedly the simplest and cheaper combination that employs [Pd(η3-C3H5)Cl]2/PPh3 at only a 1 mol-% loading with pyrrolidine as the base and in the absence of a copper salt. The coupling of sterically and electronically deactivated bromides bearing different functional groups to ar…
Direct arylation of heteroaromatic compounds with congested, functionalised aryl bromides at low palladium/triphosphane catalyst loading.
2011
International audience; A new ferrocenyl triphosphane ligand associated to palladium was found to be an efficient catalyst for the direct coupling of highly congested, functionalised aryl bromides with a variety of heteroarenes. These coupling reactions can generally be performed by using a low-loading (0.1-0.5 mol%) of the catalyst. The present protocol tolerates important and useful functional groups, which allows for further elaboration into more sophisticated heterocyclic molecules. The straightforward arylation of heteroaromatic compounds with congested ortho-substituted aryl bromides may permit further convergent syntheses of diverse ligands, biologically active molecules and molecula…
Palladium-Catalyzed Direct Arylation of Heteroaromatics with Activated Aryl Chlorides Using a Sterically Relieved Ferrocenyl-Diphosphane
2012
International audience; The palladium-catalyzed direct arylations at C3 or C4 positions of heteroaromatics are known to be more challenging than at C2 or C5 positions. Aryl chlorides are also challenging substrates for direct arylation of heteroaromatics. We observed that in the presence of a palladium-catalyst combining only 0.5 mol % of Pd(OAc)2 with the sterically relieved new ferrocenyl diphosphane Sylphos, the direct arylation at C3 or C4 of oxazoles, a benzofuran, an indole, and a pyrazole was found to proceed in moderate to high yields using a variety of electron deficient aryl chlorides. Turnover numbers up to 176 have been obtained with this catalyst. Assessment of the electron-don…
CCDC 1831928: Experimental Crystal Structure Determination
2019
Related Article: Filip Topić, Katarina Lisac, Mihails Arhangelskis, Kari Rissanen, Dominik Cinčić, Tomislav Friščić|2019|Chem.Commun.|55|14066|doi:10.1039/C9CC06735C
P-C Cross-Coupling Onto Enamides: Versatile Synthesis of α-Enamido Phosphane Derivatives
2012
We report herein the Pd-catalyzed P–C cross-coupling reac- tion between enol phosphates and secondary phosphane–bor- ane complexes or phosphane oxides. The reaction was per- formed under mild conditions, owing to Pd activation of the P–H bonds of the phosphane–boranes (or phosphane oxides) and to the powerful enol phosphate coupling reagents. New useful chiral and achiral α - β -alkenylphosphane derivatives bearing an amido group in the α -position to the P center were obtained in yields up to 70 %.
Weak Interactions between Trivalent Pnictogen Centers: Computational Analysis of Bonding in Dimers X3E···EX3 (E = Pnictogen, X = Halogen)
2009
The nature of weak interactions in dimers X3E···EX3 (E = N−Bi, X = F−I) was investigated by wave function and density functional theory (DFT)-based methods. Out of the 20 systems studied, 10 are found to be bound at the CP-MP2 and LMP2 levels of theory. Detailed partition of the interaction energy into different components revealed that dispersion is the primary force holding the dimers together but there also exists an important ionic component whose contribution increases with increasing halogen size. As expected, standard density functionals fail to describe bonding in the studied systems. However, the performance of DFT methods can be easily improved via empirical dispersion correction …
New Tetraphosphane Ligands {(X2P)2NC6H4N(PX2)2} (X = Cl, F, OMe, OC6H4OMe-o): Synthesis, Derivatization, Group 10 and 11 Metal Complexes and Catalyti…
2008
The reaction of p-phenylenediamine with excess PCl3 in the presence of pyridine affords p-C6H4[N(PCl2)2]2 (1) in good yield. Fluorination of 1 with SbF3 produces p-C6H4[N(PF2)2]2 (2). The aminotetra(phosphonites) p-C6H4[N{P(OC6H4OMe-o)2}2]2 (3) and p-C6H4[N{P(OMe)2}2]2 (4) have been prepared by reacting 1 with appropriate amount of 2-(methoxy)phenol or methanol, respectively, in the presence of triethylamine. The reactions of 3 and 4 with H2O2, elemental sulfur, or selenium afforded the tetrachalcogenides, p-C6H4[N{P(O)(OC6H4OMe-o)2}2]2 (5), p-C6H4[N{P(S)(OMe)2}2]2 (6), and p-C6H4[N{P(Se)(OMe)2}2]2 (7) in good yield. Reactions of 3 with [M(COD)Cl2] (M = Pd or Pt) (COD = cycloocta-1,5-diene)…