Xn:Harmful;
103-65-1Relevant articles and documents
ZUR BILDUNGSWEISE VON 1-PHENYLPROPYLLITHIUM AUS BENZYLLITHIUM UND ETHYLEN IN TETRAHYDROFURAN
Maercker, Adalbert,Stoetzel, Reinhard
, p. 1 - 12 (1983)
3-Phenylpropyllithium primarily formed by the addition of benzyllithium to ethylene in THF does not undergo an intramolecular 1,3-proton shift to 1-phenylpropyllithium.Fast protonation by the solvent takes place instead, yielding n-propylbenzene and new ethylene.An equilibrium is then established between n-propylbenzene and additional benzyllithium, with the formation of toluene and 1-phenylpropyllithium; the equilibrium, however, strongly favours the starting materials (K293=1.1*10-4).As, on the other hand, 1-phenylpropyllithium reacts with ethylene much more rapidly than does benzyllithium, it is removed from the equilibrium and mainly branched secondary products are still obtained.
SODIUM HYDROGEN TELLURIDE: A MECHANISTIC CHAMELEON
Barton, Derek H. R.,Bohe, Luis,Lusinchi, Xavier
, p. 6609 - 6612 (1987)
Relative rates of reduction of several α,β-unsaturated esters and styrenes added to recently obtained results from other substrates show that sodium hydrogen telluride (NaTeH) can react according to different mechanisms : nucleophilic substitution, hydride transfer, hydrogen atom transfer and electron transfer.
Selenium-assisted reduction of α- and β-diketones with carbon monoxide and water
Nishiyama, Yutaka,Inoue, Jun,Teranishi, Kazuyo,Moriwaki, Masami,Hamanaka, Sawako
, p. 6347 - 6350 (1992)
Phenyl substituted α- (PhC(=O)C(=O)R) and β-diketones (PhC(=O)CHRC(=O)R′) are reduced by carbon monoxide and water in the presence of elemental selenium to give the corresponding aromatic ketones in moderate to good yields.
Salt-free preparation of trimethylsilyl ethers by B(C6F 5)3-catalyzed transfer silylation by using a Me 3SiH surrogate
Simonneau, Antoine,Friebel, Jonas,Oestreich, Martin
, p. 2077 - 2083 (2014)
An unprecedented transfer silylation of alcohols catalyzed by the strong Lewis acid B(C6F5)3 is described. Gaseous Me3SiH is released in situ by B(C6F5) 3-catalyzed decomposition of 3-trimethylsilylcyclohexa-1,4-diene and subsequently reacts with an alcohol in a dehydrogenative Si-O coupling promoted by the same boron catalyst. Benzene and dihydrogen are formed during the reaction, but no salt waste is. This expedient protocol is applicable to several silicon groups, and the preparation of trimethylsilyl ethers presented here is potentially useful for alcohol derivatization prior to GLC analysis. Copyright
Synthesis of palladium(0) and -(ii) complexes with chelating bis(N-heterocyclic carbene) ligands and their application in semihydrogenation
Sluijter, Soraya N.,Warsink, Stefan,Lutz, Martin,Elsevier, Cornelis J.
, p. 7365 - 7372 (2013)
A transmetallation route, using silver(i) precursors, to several zero- and di-valent palladium complexes with chelating bis(N-heterocyclic carbene) ligands bearing various N-substituents has been established. The resulting complexes have been characterized by NMR and mass spectroscopy. In addition, the structure of a representative compound, [Pd0(bis-(Mes)NHC)(η2- ma)] (3a), was confirmed by X-ray crystal structure determination. In contrast to the transfer semihydrogenation, in which only low activity was observed, complex 3a showed activity (TOF = 49 molsub molcat -1 h-1) and selectivity comparable to its monodentate counterparts in the semihydrogenation of 1-phenyl-1-propyne with molecular hydrogen.
Distribution of Metal Cations in Ni-Mo-W Sulfide Catalysts
Hein, Jennifer,Gutiérrez, Oliver Y.,Schachtl, Eva,Xu, Pinghong,Browning, Nigel D.,Jentys, Andreas,Lercher, Johannes A.
, p. 3692 - 3704 (2015)
The distribution of metal cations and the morphology of unsupported NiMo, NiW, and NiMoW sulfide catalysts were explored qualitatively and quantitatively. In the bi- and trimetallic catalysts, Mo(W)S2 nanoparticles are deposited on Ni sulfide particles of varying stoichiometry and sizes (crystalline Ni9S8, and Ni3S4 were identified). These nanoparticles are stacks of Mo(W)S2 slabs with varying size, degrees of bending and mismatch between the slabs. High resolution electron microscopy and X-ray absorption spectroscopy based on particle modeling revealed a statistical distribution of Mo and W within individual layers in sulfide NiMoW, forming intralayer mixed Mo1-xWxS2. Ni is associated with MoS2, WS2, and Mo1-xWxS2 creating Ni-promoted phases. The incorporation of Ni at the edges of the slabs was the highest for sulfide NiMoW. This high concentration of Ni in sulfide NiMoW, as well as its long bent Mo1-xWxS2 slabs, were paralleled by the highest activity for nitrogen and sulfur removal from model hydrocarbons such as o-propylaniline and dibenzothiophene.
Activation of C-C Bonds via σ-Bond Metathesis: Hydroborenium-Catalyzed Hydrogenolysis of Cyclopropanes
Su, Bo,Li, Yawei,Li, Zhen Hua,Hou, Jun-Li,Wang, Huadong
, p. 4159 - 4163 (2020)
High-valent transition metal or main group complex mediated σ-bond metathesis plays an important role in the activation of covalent H-E bonds. However, its involvement in the activation of C-C bonds has remained elusive. Here we describe direct hydroboration of the C-C bonds of cyclopropanes by a hydroborenium complex. Our mechanism study suggests this reaction operates through a σ-bond metathesis pathway. With this hydroborenium complex as a catalyst, hydrogenolysis of unfunctionalized cyclopropanes was achieved, which is unprecedented for homogeneous catalysts and provides an unconventional approach for C-C bond functionalization in the absence of metals.
Transfer hydrogenation of alkenes using Ni/Ru/Pt/Au heteroquatermetallic nanoparticle catalysts: Sequential cooperation of multiple nano-metal species
Ito, Yoshikazu,Ohta, Hidetoshi,Yamada, Yoichi M. A.,Enoki, Toshiaki,Uozumi, Yasuhiro
, p. 12123 - 12126 (2014)
Quatermetallic alloy nanoparticles of Ni/Ru/Pt/Au were prepared and found to promote the catalytic transfer hydrogenation of non-activated alkenes bearing conjugating units (e.g., 4-phenyl-1-butene) with 2-propanol, where the composition metals, Ni, Ru, Pt, and Au, act cooperatively to provide significant catalytic ability. This journal is
Metal-free HB(C6F5)2-catalyzed hydrogenation of unfunctionalized olefins and mechanism study of borane-mediated σ-bond metathesis
Wang, Yuwen,Chen, Weiqiang,Lu, Zhenpin,Li, Zhen Hua,Wang, Huadong
, p. 7496 - 7499 (2013)
Out with the metal: Metal-free hydrogenation of unfunctionalized olefins can be achieved by employing HB(C6F5)2 as the catalyst. The key step in the catalytic reaction is believed to involve a novel borane-mediated σ-bond metathesis, which has been investigated both experimentally and theoretically. Copyright
Pd nanoparticles confined in mesoporous N-doped carbon silica supports: A synergistic effect between catalyst and support
Kerstien, Julius,Oliveira, Rafael L.,Schom?cker, Reinhard,Thomas, Arne
, p. 1385 - 1394 (2020)
Palladium nanoparticles of similar size were deposited on different supports, layers of carbon materials (with and without nitrogen doping) on the surface of a MCF (mesocellular foam) silica. For the generation of the N-doped carbon coatings, three different N sources were used to also investigate a possible influence of the N-doped carbon precursor and thus the structure of the N-doped carbons on their performance as catalyst support. These catalysts were tested for the Suzuki coupling and hydrogenation reactions. For the Suzuki reaction, the carbon coatings showed to increase dramatically the stability of the MCF material. Furthermore, when N-doped carbon coatings were applied, strong improvement of the stability of the catalysts was observed due to an enhanced interaction between metal nanoparticles and the support, preventing metal particle growth. In hydrogenation reactions, the presence of the N-doped carbon coating on the silica support increases the adsorption of aromatic compounds causing an enhancement of the catalytic activity of Pd NPs when compared to the non-doped supports.
