1295-35-8Relevant articles and documents
Preparation of Ni(cod)2 Using Light as the Source of Energy
Ishida, Naoki,Kamae, Yoshiki,Murakami, Masahiro
, p. 1413 - 1416 (2019)
A convenient method to prepare Ni(cod)2 from Ni(acac)2 using light as the source of energy is reported. In the first step of this process, xanthone is reductively dimerized upon irradiation of solar or LED light in 2-propanol to form a vicinal diol possessing a highly sterically congested C-C bond. In the second step, a ketyl radical derived from the diol reacts with Ni(acac)2, ultimately reducing nickel(II) to nickel(0), which is bound by 1,5-cyclooctadiene (COD) to produce Ni(cod)2. This new method obviates the need for hazardous reductants such as diisobutylaluminum hydride (DIBAH) and sodium.
Zur Lewisaciditat von Nickel(0) VII. Alkalimetall-μ3-hydrido-tetrakis(ethen)diniccolat(0)-Komplexe: (pmdta)Li(μ3-H)Ni2(C2H4)4 und (pmdta)Na(μ3-H)Ni2(C2H4)4
Porschke, Klaus Richard,Wilke, Gunther
, p. 257 - 262 (1988)
Ni(C2H4)3 reacts with alkalimetal hydridoaluminates or -gallates MAHA1/GaR3 and MAH2AlR2 (R = alkyl) in ether/pmdta at temperatures between -70 and -20 oC to yield the ion pair complexes (pmdta)MA(μ3-
Hughes
, p. 4073 (1971)
Skell, P. S.,Havel, J. J.,Williams-Smith, D. L.,McGlichey, M. J.
, (1972)
The Anionic Pathway in the Nickel-Catalysed Cross-Coupling of Aryl Ethers
Borys, Andryj M.,Hevia, Eva
, p. 24659 - 24667 (2021)
The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C?C and C?heteroatom bonds. However, the inert C(sp2)?O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.
Allylnickel(II) complexes of bulky 5-substituted-2-iminopyrrolyl ligands
Cruz, Tiago F. C.,Gomes, Pedro T.,Lopes, Patrícia S.
, (2021)
The optimized reaction between [Ni(COD)2] (COD = 1,5-cyclooctadiene) and ligand precursor 5-(2,4,6-triisopropylphenyl)-2-[N-(2,6-diisopropylphenyl)-formimino]-1H-pyrrole yielded the η3-cyclooctenyl-Ni(II) complex [Ni{κ2N,N’-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H) = N(2,6-iPr2C6H3)}(η3-C8H13)] 1. Subsequently, the η3-allyl complexes [Ni{κ2N,N’-5-R-NC4H2-2-C(H)=N(2,6-iPr2C6H3)}(η3-C3H5)] (R = 3,5-(CF3)2C6H3 (2a), 2,6-Me2C6H3 (2b), 2,4,6-iPr3C6H2 (2c) and CPh3 (2d)) were prepared in good yields via metathesis of [Ni(η3-C3H5)(μ-Br)]2 with the respective potassium 5-R-2-[N-(2,6-diisopropylphenyl)formimino]pyrrolyl salt (KLa-d). Complexes 1 and 2a-d were characterized by NMR spectroscopy, elemental analysis and complex 2d further analyzed by single crystal X-ray diffraction. Addition of excess pyridine to solutions of complexes 2a-d led to the observation of a fluxional process that, according to VT-NMR experiments, corresponds to a pyridine-assisted cis–trans isomerization process occurring in these complexes, via a η3-η1-η3 haptotropic shift of the allyl ligand, with ΔG? values in range of 9.5–17.3 kcal mol?1. Additionally, complexes 2a-d, when activated by B(C6F5)3, slowly catalyzed the isomerization of hex-1-ene to mixtures of internal olefins.
Preparation method of bilastine key intermediate
-
Paragraph 0040-0041, (2021/08/25)
The invention belongs to the technical field of drug synthesis, and relates to 2 - (4 - (2 - (4 -ethoxyethyl) 1 - benzo [2 -] imidazol - 1H - yl) piperi d-ethyl) phenyl) -2 -methylpropionate (-1 -), and a -2 - complex and II acid are used as a catalyst to condensation the enolate anion with the compound (16 15) to form a target product II Ni Lewis. The invention aims to provide a short synthetic route. The provided route raw material condition is mild, the yield is high, the tedious building quaternary carbon atom method reported in the traditional process is avoided, and the method is suitable for industrial production.
16-Electron Nickel(0)-Olefin Complexes in Low-Temperature C(sp2)-C(sp3) Kumada Cross-Couplings
Lutz, Sigrid,Nattmann, Lukas,N?thling, Nils,Cornella, Josep
supporting information, p. 2220 - 2230 (2021/05/07)
Investigations into the mechanism of the low-temperature C(sp2)-C(sp3) Kumada cross-coupling catalyzed by highly reduced nickel-olefin-lithium complexes revealed that 16-electron tris(olefin)nickel(0) complexes are competent catalysts for this transformation. A survey of various nickel(0)-olefin complexes identified Ni(nor)3as an active catalyst, with performance comparable to that of the previously described Ni-olefin-lithium precatalyst. We demonstrate that Ni(nor)3, however, is unable to undergo oxidative addition to the corresponding C(sp2)-Br bond at low temperatures (a nickel(0)-alkylmagnesium complex. We demonstrate that this unique heterobimetallic complex is now primed for reactivity, thus cleaving the C(sp2)-Br bond and ultimately delivering the C(sp2)-C(sp3) bond in high yields.