23674-13-7Relevant articles and documents
Evaluation of the Transferability of the “Flexible Steric Bulk” Concept from N-Heterocyclic Carbenes to Planar-Chiral Phosphinoferrocenes and their Electronic Modification
Korb, Marcus,Schaarschmidt, Dieter,Grumbt, Martin,K?nig, Matthias,Lang, Heinrich
supporting information, p. 2968 - 2982 (2020/07/02)
The concept of “flexible steric bulk” is discussed at 2-phenylvinyl-1-phosphinoferrocenes. The introduction of freely rotatable 1'-silyl groups increases the catalytic productivity within the synthesis of tri-ortho-substituted biaryls by Suzuki–Miyaura C,C cross-coupling reactions, giving higher yields with 1/4 of catalyst concentration than for the non-silylated derivatives. Electronic modification of the P and the vinyl donor functionalities was investigated by introducing substituents in the para positions of both groups. Therein, electron-withdrawing phosphines increased the yield from 78 to 91 percent for a given biaryl, by changing from a diphenylphosphino to the P(p-CN-C6H4)2 unit. Opposite results, obtained from electron-donating and sterically demanding phosphines, were in accordance with the 1J(31P,77Se) values. However, the electron density of the ferrocenyl backbone, expressed by the redox potential of the first ferrocenyl-related redox process, cannot be correlated with the donor-properties at the P atom. Changing from a PPh2-substituted ferrocene to a (RA)-1,1'-binaphthyl-containing phosphonite, a complex interaction between the axial- and the planar-chiral motifs occurs, resulting a change of the absolute biaryl configuration.
SYNTHESIS OF PHOSPHINE LIGANDS BEARING TUNABLE LINKAGE: METHODS OF THEIR USE IN CATALYSIS
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Page/Page column 16; 17, (2017/12/02)
A series of novel linked indolyl phosphine ligands for transition metals, the synthesis thereof and their use in catalytic coupling reactions are provided. The ligands provide improvements of trasition-metal-catalyzed reactions, including the range of substrates scope, reaction conditions and efficieny.
Resorcinarene-Based o-Biarylphosphines in Palladium-Catalysed Suzuki–Miyaura Cross-Coupling Reactions of Bulky Substrates
Elaieb, Fethi,Sémeril, David,Matt, Dominique
supporting information, p. 685 - 693 (2017/02/05)
Two o-biarylphosphines, in which the arene ring remote from the phosphorus atom is part of a resorcin[4]arene cavitand, have been synthesised, characterised by X-ray diffraction and assessed in the cross-coupling reactions of bulky aryl chlorides with sterically hindered arylboronic acids. Only atropisomers with externally located P atoms were obtained. The resorcinarene ligand with the o-PCy2C6H4substituent was found to be more efficient than the Buchwald analogue SPhos in catalysing coupling reactions, reacting around 1.4 times faster. Its superior performance has been attributed to the permanent exo positioning of the metal centre, which engenders steric interactions with two pentyl substituents and therefore facilitates the reductive elimination step.