637-50-3Relevant articles and documents
Bumgardner, Jwerks
, p. 431 (1968)
HETEROPOLY ANION-ASSISTED Rh CATALYSIS REVEALED IN THE HOMOGENEOUS SELECTIVE HYDROGENATION
Urabe, Kazuo,Tanaka, Yoshiyuki,Izumi, Yusuke
, p. 1595 - 1596 (1985)
When coupled with lithium salt of heteropoly acid, the Wilkinson complex RhCl(PPh3)3 catalyst became very active and selective for the semihydrogenation of alkyne to alkene and, more interestingly, exhibited sharp substrate-selectivity in hydrogenation of substituted alkenes.
The N-Methylpyrrolidone (NMP) Effect in Iron-Catalyzed Cross-Coupling with Simple Ferric Salts and MeMgBr
Mu?oz, Salvador B.,Daifuku, Stephanie L.,Sears, Jeffrey D.,Baker, Tessa M.,Carpenter, Stephanie H.,Brennessel, William W.,Neidig, Michael L.
, (2018)
The use of N-methylpyrrolidone (NMP) as a co-solvent in ferric salt catalyzed cross-coupling reactions is crucial for achieving the highly selective, preparative scale formation of cross-coupled product in reactions utilizing alkyl Grignard reagents. Desp
Isomerization of 3-phenyl-1-propene (allylbenzene) over base catalysts
Marinas,Aramendia,Borau,Jimenez,Marinas,Urbano
, p. 556 - 559 (2002)
The isomerization of 3-phenyl-1-propylene (allylbenzene) to 1-phenyl-1-propylene (β-methylstyrene) (cis + trans) was studied as a new test reaction for base catalysts. The injection of pure trans-β-methylstyrene (without catalyst) only yielded 1% of the other isomer (cis-βmethylstyrene). The injection of pure trans-β-methylstyrene, in the presence of catalysts, yielded small quantities of allylbenzene and cis-β-methylstyrene. Poisoning of the catalyst with CO2 led to a sharp decrease in activity. The trans/cis ratio was ～ six for all the catalysts.
Identifying and Evading Olefin Isomerization Catalyst Deactivation Pathways Resulting from Ion-Tunable Hemilability
Dodge, Henry M.,Kita, Matthew R.,Chen, Chun-Hsing,Miller, Alexander J. M.
, p. 13019 - 13030 (2020)
Hemilabile ligands are found in many leading organometallic catalysts, but it can be challenging to tune the degree of hemilability in a particular catalyst. This work explores the impact of cation-tunable hemilability on the speciation of iridium(III) pincer-crown ether catalysts during high-activity olefin isomerization. Under conditions where strong cation-macrocycle interactions are fostered and terminal olefin has been consumed, labilization of the aza-crown ether group leads to an η6-arene complex, wherein the pincer ligand is metallated at a different position. Arene complexes of styrene, naphthalene, and mesitylene were independently synthesized and found to exhibit diminished catalytic activity for allylbenzene isomerization. In response to these findings, a previously unreported catalyst bearing a synthetically modified pincer ligand was designed, resulting in a refined system that maintains high activity even when arene complexes are formed.
Regioselective Deaminative Allylation of Aliphatic Amines via Dual Cobalt and Organophotoredox Catalysis
Sekino, Tomoyuki,Sato, Shunta,Yoshino, Tatsuhiko,Kojima, Masahiro,Matsunaga, Shigeki
supporting information, p. 2120 - 2124 (2022/03/27)
Despite the rapid progress in C-C bond-forming reactions using Katritzky salts, their deaminative allylation remains a challenge. Inspired by the metallaphotoredox-catalyzed allylic substitution regime, here, we report the deaminative allylation of Katritzky salts via cobalt/organophotoredox dual catalysis. This cross-electrophile coupling enables regioselective allylation using a variety of allylic esters, overcoming the substrate limitations of reported protocols. Mechanistic studies indicate the involvement of a π-allyl cobalt complex as a radicalophile that mediates C-C bond formation.
Highly selective semi-hydrogenation of alkynes with a Pd nanocatalyst modified with sulfide-based solid-phase ligands
Huang, Lingqi,Hu, Kecheng,Ye, Ganggang,Ye, Zhibin
, (2021/03/30)
Soluble small molecular/polymeric ligands are often used in Pd-catalyzed semi-hydrogenation of alkynes as an efficient strategy to improve the selectivity of targeted alkene products. The use of soluble ligands requires their thorough removal from the reaction products, which adds significant extra costs. In the paper, commercially available, inexpensive, metallic sulfide-based solid-phase ligands (SPL8-4 and SPL8-6) are demonstrated as simple yet high-performance insoluble ligands for a heterogeneous Pd nanocatalyst (Pd@CaCO3) toward the semi-hydrogenation of alkynes. Based on the reactions with a range of terminal and internal alkyne substrates, the use of the solid-phase ligands has been shown to markedly enhance the selectivity of the desired alkene products by efficiently suppressing over-hydrogenation and isomerization side reactions, even during the long extension of the reactions following full substrate conversion. A proper increase in the dosage or a reduction in the average size of the solid-phase ligands enhances such effects. With their insoluble nature, the solid-phase ligands have the distinct advantage in their simple, convenient recycling and reuse while without contaminating the products. A ten-cycle reusability test with the SPL8-4/Pd@CaCO3 catalyst system confirms its well-maintained activity and selectivity over repeated uses. A mechanistic study with x-ray photoelectron spectroscopy indicates that the solid-phase ligands have electronic interactions with Pd in the supported catalyst, contributing to inhibit the binding and further reaction of the alkene products. This is the first demonstration of solid-phase ligands for highly selective semi-hydrogenation of alkynes, which show strong promise for commercial applications.
