Selective Liquid-Phase Semihydrogenation of Functionalized Acetylenes and Propargylic Alcohols with Silica-Supported Bimetallic Palladium−Copper Catalysts
摘要:
Silica-supported, bimetallic palladium-copper catalysts were prepared in solution under mild conditions by reacting lithium di(4-tolyl)cuprate with palladium acetate in the presence of silica particles. Small bimetallic palladium-copper particles were deposited on the silica surface as confirmed with TEM-EDAX and EXAFS. The new material has been applied as catalyst in the liquid-phase semihydrogenation of mono- and disubstituted alkynes and showed high selectivity toward the cis-alkenes. The influence of addition of quinoline or potassium hydroxide to the semihydrogenation reaction mixture and the effects of exposure of the catalyst to air before use have been investigated.
Silicon(II) Cation Cp*Si:<sup>+</sup>X<sup>–</sup>: A New Class of Efficient Catalysts in Organosilicon Chemistry
作者:Elke Fritz-Langhals
DOI:10.1021/acs.oprd.9b00260
日期:2019.11.15
The catalytic activity of the pentamethylcyclopentadienylsilicon(II) cation Cp*Si:+ was investigated. It was shown that Cp*Si:+ efficiently catalyzes reactions of technical relevance in organosiliconchemistry: Cp*Si:+ proved to be a very efficient nonmetallic catalyst for the hydrosilylation of olefins at low catalyst amounts of <0.01 mol % and for the Piers–Rubinsztajn reaction in order to make controlled
Comparative Study of the Electronic Structures of μ-Oxo, μ-Nitrido, and μ-Carbido Diiron Octapropylporphyrazine Complexes and Their Catalytic Activity in Cyclopropanation of Olefins
作者:Lucie P. Cailler、Martin Clémancey、Jessica Barilone、Pascale Maldivi、Jean-Marc Latour、Alexander B. Sorokin
DOI:10.1021/acs.inorgchem.9b02718
日期:2020.1.21
The electronic structure of three single-atom bridged diiron octapropylporphyrazine complexes (FePzPr8)2X having Fe(III)-O-Fe(III), Fe(III)-N-Fe(IV) and Fe(IV)-C-Fe(IV) structural units was investigated by Mössbauer spectroscopy and density functional theory (DFT) calculations. In this series, the isomer shift values decrease, whereas the values of quadrupole splitting become progressively greater
Selective cross-disproportion between vinylsilanes and various mono-substituted alkenes is catalysed by [RuCl(CO)H(PPh3)3]1; the mechanism of this reaction has been elucidated based on reactions of 1 with vinylsilanes as well as those of the resulting ruthenium–silyl complex with alkenes.
The Electron as a Protecting Group. 2. Generation of Benzocyclobutadiene Radical Anion in the Gas Phase and an Experimental Determination of the Heat of Formation of Benzocyclobutadiene
作者:Katherine M. Broadus、Steven R. Kass
DOI:10.1021/ja002352b
日期:2000.11.1
Benzocyclobutadiene radical anion (5) was synthesized in the gasphase by three independent approaches: collision-induced dissociation (CID) of 1,2-benzocyclobutenedicarboxylate, reaction of 2-tri...
6Li and 13C NMR spectra of 1,2-dilithio[tetrakis(trimethylsilyl)]ethane revealed a doubly bridged π-structure in aromatic solvents similar to that observed in the crystals. However, the dianion in THF, which was found to exist as a solvent–separated ion pair of Li+(THF)4 and a species bridged by one Li atom, was reactive to undergo anionic rearrangement.