4683-67-4Relevant academic research and scientific papers
Visible-Light Controlled Divergent Catalysis Using a Bench-Stable Cobalt(I) Hydride Complex
Beltran, Frédéric,Bergamaschi, Enrico,Teskey, Christopher J.
supporting information, p. 5180 - 5184 (2020/04/22)
While the use of visible light in conjunction with transition metal catalysis offers powerful opportunities to switch between on/-off states of catalytic activity, the next frontier would be the ability to switch the actual function of the catalyst and resulting products. Here we report such an example of multi-dimensional catalysis. Featuring an easily prepared, bench-stable cobalt(I) hydride complex in conjunction with pinacolborane, we can switch the reaction outcome between two widely employed transformations, olefin migration and hydroboration, with visible light as the trigger.
Method for synthesizing E-methyl styrene compound
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Page/Page column 10, (2020/03/25)
The method for preparing E-pyridyl or alkyl-substituted,bipyridine, in a solvent, in the presence of nitrogen protection, in, reaction 0 °C -50 °C in the presence of a metal nickel salt 24 - 36h, ligand and an additive is E, and the preparation method disclosed by the invention has the advantages, cheap 2,2 ’ - raw materials, easiness in obtaining 2,2 ’ - and the like. The ligand is,bipyridine or an alkyl-substituted bipyridyl compound, in the. presence of a nitrogen, protection agent, in a solvent.
A Next-Generation Air-Stable Palladium(I) Dimer Enables Olefin Migration and Selective C?C Coupling in Air
Kundu, Gourab,Rissanen, Kari,Schoenebeck, Franziska,Sperger, Theresa
supporting information, p. 21930 - 21934 (2020/10/02)
We report a new air-stable PdI dimer, [Pd(μ-I)(PCy2tBu)]2, which triggers E-selective olefin migration to enamides and styrene derivatives in the presence of multiple functional groups and with complete tolerance of air. The same dimer also triggers extremely rapid C?C coupling (alkylation and arylation) at room temperature in a modular and triply selective fashion of aromatic C?Br, C?OTf/OFs, and C?Cl bonds in poly(pseudo)halogenated arenes, displaying superior activity over previous PdI dimer generations for substrates that bear substituents ortho to C?OTf.
Tandem Olefin Isomerization/Cyclization Catalyzed by Complex Nickel Hydride and Br?nsted Acid
Kathe, Prasad M.,Caciuleanu, Alexandru,Berkefeld, Andreas,Fleischer, Ivana
, p. 15183 - 15196 (2020/11/30)
We disclose a nickel/Br?nsted acid-catalyzed tandem process consisting of double bond isomerization of allyl ethers and amines and subsequent intramolecular reaction with nucleophiles. The process is accomplished by [(Me3P)4NiH]N(SO2CF3)2 in the presence of triflic acid. The methodology provides rapid access to tetrahydropyran-fused indoles and other oxacyclic scaffolds under very low catalyst loadings.
In situ generated bulky palladium hydride complexes as catalysts for the efficient isomerization of olefins. Selective transformation of terminal alkenes to 2-alkenes
Gauthier, Delphine,Lindhardt, Anders T.,Olsen, Esben P. K.,Overgaard, Jacob,Skrydstrup, Troels
supporting information; experimental part, p. 7998 - 8009 (2010/08/04)
Application of an in situ generated bulky palladium(II) hydride catalyst obtained from a 1:1:1 mixture of Pd(dba)2, P(tBu)3, and isobutyryl chloride provides an efficient protocol for the isomerization and migration of a variety of olefins. In addition to the isomerization of (Z)- to (E)-olefins, the conjugative migration of allylbenzenes, allyl ethers, and amines was effectively achieved in near-quantitative yields and with excellent functional group tolerance. Catalyst loadings in the range of 0.5-1.0 mol % were typically applied, but even loadings as low as 0.25 mol % could be achieved when the reactions were performed under neat conditions. More interestingly, the investigated catalyst proved to be selective for converting terminal alkenes to 2-alkenes. This one-carbon migration process for monosubstituted olefins provides an alternative catalyst, which bridges the gap between the allylation and propenylation/vinylation protocols. Several substrates, including homoallylic alcohols and amines, were selectively transformed into their corresponding 2-alkenes, and examples using enantiomerically enriched substrates provided products without epimerization at the allylic stereogenic carbon centers. Finally, some mechanistic investigations were undertaken to understand the nature of the active in situ generated Pd-H catalyst. These studies revealed that the catalytic system is highly dependent on the large steric demand of the P(tBu)3 ligand. The use of an alternative ligand, cataCXium PinCy, also proved effective for generating an active catalyst, and it was demonstrated in some cases to display better selectivity for the one-carbon shifts of terminal olefins. A possible intermediate involved in the preparation of the active catalyst was characterized by its single-crystal X-ray structure, which revealed a monomeric tricoordinated palladium(II) acyl complex, bearing a chloride ligand.
