62676-19-1Relevant academic research and scientific papers
Chemo- and regioselective dimerization of terminal alkynes promoted by methylaluminoxane
Dash, Aswini K.,Eisen, Moris S.
, p. 737 - 740 (2000)
(figure presented) Methylalumoxane (MAO) was found to be an active catalytic precursor for the chemo- and regioselective dimerization of a wide range of aryl-and alkyl-substituted terminal alkynes yielding the corresponding geminal dimers A. For an olefin
Rhodium(I)-N-heterocyclic carbene catalyst for selective coupling of N-vinylpyrazoles with alkynes via C-H activation
Azproz, Ramn,Rubio-Prez, Laura,Di Giuseppe, Andrea,Passarelli, Vincenzo,Lahoz, Fernando J.,Castarlenas, Ricardo,Prez-Torrente, Jess J.,Oro, Luis A.
, p. 4244 - 4253 (2014)
The complex [Rh(μ-Cl)(IPr)(η2-coe)]2 {IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-carbene, coe = cis-cyclooctene} efficiently catalyzes the coupling of alkynes and N-vinylpyrazole via C-H activation, leading to Markovnikov-selecti
Alkynyldichlorogalliums are Unstable in Hydrocarbon Solvents Dimerization of Alkynyldichlorogalliums via Carbogallation
Yamaguchi, Masahiko,Hayashi, Akio,Hirama, Masahiro
, p. 1093 - 1094 (1995)
Alkynyldichlorogalliums dimerize in hydrocarbon solvents via carbogallation giving 1,1-dimetallo-1-buten-3-yne derivatives.
Variation on the π-Acceptor Ligand within a RhI?N-Heterocyclic Carbene Framework: Divergent Catalytic Outcomes for Phenylacetylene-Methanol Transformations
Galiana-Cameo, María,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.,Di Giuseppe, Andrea,Castarlenas, Ricardo
, p. 2947 - 2957 (2021/07/16)
A series of neutral and cationic rhodium complexes bearing IPr {IPr=1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-carbene} and π-acceptor ligands are reported. Cationic species [Rh(η4-cod)(IPr)(NCCH3)]+ and [Rh(CO)(IPr)(L)2]+ (L=pyridine, CH3CN) were obtained by chlorido abstraction in suitable complexes, whereas the cod-CO derivative [Rh(η4-cod)(IPr)(CO)]+ was formed by the carbonylation of [Rh(η4-cod)(IPr)(NCCH3)]+. Alternatively, neutral derivatives of type RhCl(IPr)(L)2 {L=tBuNC or P(OMe)3} can be accessed from [Rh(μ-Cl)(η2-coe)(IPr)]2. In addition, the mononuclear species Rh(CN)(η4-cod)(IPr) was prepared by cyanide-chlorido anion exchange, which after carbonylation afforded the unusual trinuclear compound [Rh{1κC,2κN-(CN)}(CO)(IPr)]3. Divergent catalytic outcomes in the phenylacetylene-methanol transformations have been observed. Thus, enol ethers, arisen from hydroalkoxylation of the alkyne, were obtained with neutral Rh?CO catalyst precursors whereas dienol ethers were formed with cationic catalysts. Variable amounts of alkyne dimerization, cyclotrimerization or polymerization products were obtained in the absence of a strong π-acceptor ligand on the catalyst.
Stereo- A nd regioselective dimerization of alkynes to enynes by bimetallic syn-carbopalladation
Pfeffer, Camilla,Wannenmacher, Nick,Frey, Wolfgang,Peters, René
, p. 5496 - 5505 (2021/05/31)
Enynes are important motifs in bioactive compounds. They can be synthesized by alkynea'alkyne couplings for which a number of mechanisms have been suggested depending on catalyst type and dominant product isomers. Regarding bimetallic pathways, hydrometalations and anti-carbopalladations have been discussed to account for the formation of geminally substituted and (Z)-configured enynes, respectively. Here we report a bimetallic alkynea'alkyne coupling that yields (E)-configured enynes. An unusual type of acetylide Pd bridging was found in putative catalytic intermediates which is arguably responsible for the regio- A nd stereochemical reaction outcome. Mechanistic studies suggest that a double μa'κ:η2 acetylide bridging enables a bimetallic syn-carbometalation. Interestingly, depending on the reaction conditions, it is also possible to form the geminal regioisomer as major product with the same catalyst. This regiodivergent outcome is explained by bi-versus monometallic reaction pathways.
Construction of modular Pd/Cu multimetallic chainsvialigand- And anion-controlled metal-metal interactions
Deolka, Shubham,Fayzullin, Robert R.,Govindarajan, Ramadoss,Khaskin, Eugene,Khusnutdinova, Julia R.,Pal, Shrinwantu,Rivada-Wheelaghan, Orestes
supporting information, p. 10206 - 10209 (2021/10/14)
The presence of Pd?Cu and Pd?Pd interactions as well as the order of metal atoms in a chain held by a modular polynucleating ligand is controlled by the coordinating ability of the anions, leading to selective formation of bi- and tetranuclear Pd/Cu and P
Synthesis of 6-Adamantyl-2-pyridone and Reversible Hydrogen Activation by the Corresponding Bis(perfluorophenyl)borane Complex
Wech, Felix,Müller, Tizian,Becker, Jonathan,Gellrich, Urs
, p. 666 - 672 (2020/11/19)
We herein describe the two-step synthesis of 6-Adamantyl-2-pyridone from 1-Acetyladamantane. The borane complex derived from 6-Adamantyl-2-pyridone and the Piers borane liberates dihydrogen at 60 °C. The reverse reaction, hydrogen activation by the formed pyridonate borane is accomplished under mild conditions. The mechanism of the hydrogen activation is studied by DFT computations.
Metal-Ligand Cooperative Proton Transfer as an Efficient Trigger for Rhodium-NHC-Pyridonato Catalyzed gem-Specific Alkyne Dimerization
Galiana-Cameo, María,Urriolabeitia, Asier,Barrenas, Eduardo,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.,Di Giuseppe, Andrea,Polo, Víctor,Castarlenas, Ricardo
, p. 7553 - 7567 (2021/06/30)
The mononuclear square-planar Rh{κ2-X,N-(Xpy)}(η2-coe)(IPr) (X = O, NH, NMe, S) complexes have been synthesized from the dinuclear precursor [Rh(μ-Cl)(IPr)( η2-coe)]2 and the corresponding 2-heteroatom-pyridinate salts. The Rh-NHC-pyridinato derivatives a
N-Heterocyclic Carbene-Catalyzed 1,4-Alkylacylation of 1,3-Enynes
Cai, Yuxing,Chen, Jiean,Huang, Yong
, p. 9251 - 9255 (2021/11/30)
The radical relay coupling reaction recently emerged as a powerful synthetic strategy for producing tetrasubstituted allenes. However, bond-forming processes involving the allenyl radical intermediate are mostly limited to those promoted by transition metals. In this report, we describe that a ketyl radical generated from single-electron oxidation of the Breslow intermediate is an excellent coupling partner of allenyl radicals. An organocatalytic 1,4-alkylacylation of 1,3-enynes occurred smoothly in the presence of an aldehyde, a radical precursor, and an N-heterocyclic carbene catalyst. This transformation showed remarkable tolerance to both aromatic and aliphatic aldehydes, enyne substitution, and diversified radical precursors.
Ru-catalyzed (E)-specific ortho-C-H alkenylation of arenecarboxylic acids by coupling with alkenyl bromides
Belitz, Florian,Goo?en, Lukas J.,Hu, Zhiyong,Papp, Florian,Zhang, Guodong
supporting information, p. 3541 - 3545 (2021/05/31)
In the presence of [p-cymene)RuCl2]2, (E)-configured alkenyl bromides couple with aromatic carboxylates to form ortho-vinylbenzoic acids. This C-H vinylation proceeds in high yields without any activating phosphine ligands and has an excellent functional group tolerance. Starting from commonly available (E/Z)-mixtures of alkenyl bromides, (E)-configured vinyl arenes or dienes are formed exclusively. Mechanistic studies show that this selectivity is achieved because the (E)-configured alkenyl bromides undergo a smooth coupling, whereas the (Z)-isomers are rapidly eliminated with the formation of alkynes.
