96555-88-3Relevant articles and documents
Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C?O Bond Activation
Hu, Wei-Qiang,Pan, Shen,Qing, Feng-Ling,Vicic, David A.,Xu, Xiu-Hua
, p. 16076 - 16082 (2020/07/04)
The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3). The strategy relies on PMe3-promoted oxidative addition and transmetalation, and CCl3CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.
New nickel-containing homogeneous hydrogenation catalysts structures of [Ni(o-MeO-dpppol)Cl2] and [Ni(dcpe)Cl2]
Angulo, Ingrid M.,Bouwman, Elisabeth,Van Gorkum, Remy,Lok, Sandra M.,Lutz, Martin,Spek, Anthony L.
, p. 97 - 106 (2008/10/08)
The didentate phosphane ligands 1,3-bis(di(ortho-methoxyphenyl)phosphanyl)-2-propanol (o-MeO-dpppol) and 1,2bis(dicyclohexylphosphanyl)ethane (dcpe) have been used in a study towards catalytic hydrogenation using homogeneous nickel catalysts. The nickel halide complexes [Ni(o-MeO-dpppol)X2] and [Ni(dcpe)X2] (X = Cl, Br or I) have been synthesized and were characterized using electronic absorption and IR spectroscopy. The structures of the complexes [Ni(o-MeO-dpppol)Cl2] and [Ni(dcpe)Cl2] have been determined by X-ray crystallography. The nickel ions in these complexes are in (distorted) square-planar geometries with NiP2Cl2 chromophores. The synthesized halide complexes and in situ mixtures of nickel acetate and the ligands were tested on catalytic activity in homogeneous hydrogenation. The ligand dcpe yields very active catalysts; turnover numbers up to 3000 in 1 h have been obtained. Generally, it appeared that the catalytic activities are higher in methanol than in methanol/dichloromethane mixtures. It was found that the catalytic activities observed for complexes containing the ligand o-MeO-dpppol are less reproducible than those of catalysts with the ligand dcpe. This lower reproducibility is probably related to the fact that the former ligand is more readily oxidized.
Preparation and reactivity of nickel(0) complexes with η2-coordinated alkynylphosphines
Bennett, Martin A.,Castro, Jeffrey,Edwards, Alison J.,Kopp, Mike R.,Wenger, Eric,Willis, Anthony C.
, p. 980 - 989 (2008/10/08)
The η2-alkynylphosphine complexes [Ni(η2-Ph2PC≡CR)(dcpe)] (R = Me (1a), CO2Me (1b), Ph (1c)), which are formed by displacement of ethylene from [Ni(C2H4)(dcpe)] by the corresponding alkynylphosphine, react with HCl (1 equiv) to give five-coordinate nickel(II) complexes, [NiCl{C(=CHR)PPh2-κP,C1}(dcpe)] (R = Me (2a), CO2Me (2b), Ph (2c)), which contain a coordinated methylenephosphanickelacyclopropane fragment. In the case of 1a, the proton adds regiospecifically at the carbon atom bearing the methyl group. This mode of addition is favored for 1b,c, but small amounts of the addition products [NiCl{η1-C(R)=CH(PPh2)}(dcpe)] (R = CO2Me (3b), Ph (3c)), arising from addition at the PPh2-bearing carbon atoms, are also formed. Unsaturated molecules such as CS2 and CO2 insert into the Ni-P bonds of complexes 2a,c to give five-membered nickelacycles. Complexes 1a, 2a,c, and 3c have been structurally characterized by X-ray diffraction analysis.