80254-68-8Relevant articles and documents
Cobalt-Catalyzed Biaryl Couplings via C-F Bond Activation in the Absence of Phosphine or NHC Ligands
Wei, Juan,Liu, Kun-Ming,Duan, Xin-Fang
, p. 1291 - 1300 (2017/02/10)
A highly general and selective Co-catalyzed biaryl coupling through C-F cleavage under phosphine or NHC-free conditions was described. A broad range of aryl fluorides including unactivated fluorides as well as those with sensitive functionalities could couple with various Ti(OEt)4-mediated aryl Grignard reagents with high selectivity under the catalysis of CoCl2/DMPU. Importantly, selective C-F bond activation couplings between two types of fluorines (difluorinated aromatics and on two different coupling partners) and in the presence of C-Cl or C-Br bonds could also be achieved.
Air-stable and catalytically active phosphinous acid transition-metal complexes
Kurscheid, Boris,Belkoura, Lhoussaine,Hoge, Berthold
experimental part, p. 1329 - 1334 (2012/04/10)
Secondary phosphane oxides R2P(O)H are most frequently used as preligands for phosphinous acid R2POH (R = alkyl, aryl) transition-metal complexes, which are very efficient catalysts for cross-coupling reactions. To investigate the influence of electron-deficient substituents on the catalytic activity, the coordination properties of bis(trifluoromethyl)-, bis(pentafluoroethyl)-, and bis[2,4-bis(trifluoromethyl) phenyl]phosphinous acid toward catalytically relevant metals, such as palladium and platinum, are studied. The novel phosphinous acid palladium complexes reveal a high catalytic activity in Heck and Suzuki cross-coupling reactions. Because of the strong dependence of these processes on the reaction conditions, a systematic solvent and base screening with 1-bromo-3-fluorobenzene and phenyl boronic acid as model reactants is performed. The most efficient solvent/base system consists of 2-propanol and potassium phosphate, providing a full conversion and a TON of around 10 000 after 20 h at room temperature with a catalyst loading of 0.01 mol % palladium. A catalyst loading of only 0.004 mol % palladium still leads to a nearly full conversion after 20 h at room temperature. During the catalytic reaction, the formation of the corresponding phosphinic acid R2P(O)OH is observed. Further investigations lead to the conclusion that palladium nanoparticles represent the catalytically active species. We also succeeded in the generation of palladium nanoparticles, which exhibit an extremely high catalytic activity in Suzuki cross-coupling reaction with TONs over 60 000 and TOFs larger than 40 000.
F-NMR-spectroscopy for the identification of photo products generated from aromatic iodo compounds - IV
Kelm, J.,Strauss, K.
, p. 689 - 692 (2007/10/02)
The investigation demonstrates the analytical power of F-NMR spectroscopy for the identification of isomeric substituted fluorobiphenyls.The biphenyls are formed by u.v. irradiation of iodobenzenes in aromatic solvents.A special procedure for the identification is outlined and tendencies of the results-chemical shifts and relative rates for the production of isomers-are discussed in consideration of electronic and steric substituent effects.
