101093-37-2Relevant academic research and scientific papers
E-selective semi-hydrogenation of alkynes with dinuclear iridium complexes under atmospheric pressure of hydrogen
Higashida, Kosuke,Mashima, Kazushi
, p. 866 - 868 (2016)
Semi-hydrogenation of alkynes was catalyzed by halide-bridged dinuclear iridium complexes, yielding (E)-alkenes with high selectivity. Mechanistic studies conducted with monohydride dinuclear species, dihydride mononuclear species, and trihydride dinuclear species led us to propose a mechanism involving dual cycles.
N-donor 2-(Sulfonamido)benzamide ligands, their palladium(II) coordination species and C–C coupling catalysis efficiencies
Oloyede, Hammed Olawale,G?rls, Helmar,Orighomisan Woods, Joseph Anthony,Plass, Winfried,Eseola, Abiodun Omokehinde
, p. 336 - 344 (2019)
A series of synthetically accessible ligands based on new 2-(R-sulfonamido)benzamide have been prepared (R = methyl for H3M; R = 4-toly for H3T and T2CN; R = 2,4,6-triisopropylphenyl for H3iP and HiPCN). The R-substituents were selected to vary in sizes. Allowing ligand H3iP and palladium acetate to stand in solvent leads to self-assembly of the well-defined solvent- and stoichiometry-controlled tetranuclear or hexanuclear coordination macromolecules Pd4(iP)2 and (PdHiP)6, which were analysed by X-ray crystallography. It was observed that palladium active species for Suzuki coupling catalysis could be stabilized by these simple and synthetically assessable N-donor ligands as revealed by turnover frequencies reaching 5500 h?1. Electronic features of these N-donors appear to be more important than the steric properties.
Bis(bipyridine) ruthenium(ii) bis(phosphido) metalloligand: Synthesis of heterometallic complexes and application to catalytic (E)-selective alkyne semi-hydrogenation
Takemoto, Shin,Kitamura, Manami,Saruwatari, Shuhei,Isono, Atsutaka,Takada, Yoko,Nishimori, Rie,Tsujiwaki, Mina,Sakaue, Naoki,Matsuzaka, Hiroyuki
, p. 1161 - 1165 (2019)
The first phosphido derivative of the bis(bipyridine) ruthenium(ii) fragment, cis-[(bpy)2Ru(PPh2)2] ([RuP2]), has been developed and applied as a P-donor metalloligand to form new Ru-Rh, Ru-Ir and Ru2Cu2 heterometallic complexes. The Ru-Ir hydride complex [([RuP2])IrH(NCMe)3][BF4]2 exhibits significant catalytic activity for (E)-selective semi-hydrogenation of alkynes.
Layered double hydroxide supported nanopalladium catalyst for Heck-, Suzuki-, Sonogashira-, and Stille-type coupling reactions of chloroarenes
Choudary, Boyapati M.,Madhi, Sateesh,Chowdari, Naidu S.,Kantam, Mannepalli L.,Sreedhar, Bojja
, p. 14127 - 14136 (2002)
Layered double hydroxide and Merrifield resin supported nanopalladium(0) catalysts are prepared by an exchange of PdCl42- followed by reduction and well characterized for the first time. The ligand-free heterogeneous layered double hydroxide supported nanopalladium (LDH-Pd0) catalyst using the basic LDH in place of basic ligands indeed exhibits higher activity and selectivity in the Heck olefination of electron-poor and electron-rich chloroarenes in nonaqueous ionic liquids (NAIL) over the homogeneous PdCl2 system. Using microwave irradiation, the rate of the Heck olefination reaction is accelerated, manifold with the highest turnover frequency ever recorded in the case of both electron-poor and electron-rich chloroarenes. The basic LDH-Pd0 shows a superior activity over a range of supported catalysts, from acidic to weakly basic Pd/C, Pd/SiO2, Pd/Al2O3, and resin-PdCl42- in the Heck olefination of deactivated electron-rich 4-chloroanisole. The use of LDH-Pd0 is extended to the Suzuki-, Sonogashira-, and Stille-type coupling reactions of chloroarenes in an effort to understand the scope and utility of the reaction. The catalyst is quantitatively recovered from the reaction by a simple filtration and reused for a number of cycles with almost consistent activity in all the coupling reactions. The heterogeneity studies provide an insight into mechanistic aspects of the Heck olefination reaction and evidence that the reaction proceeds on the surface of the nanopalladium particles of the heterogeneous catalyst. TEM images of the fresh and used catalyst indeed show that the nanostructured palladium supported on LDH remains unchanged at the end of the reaction, while the XPS and evolved gas detection by TGA-MS of the used catalyst identify ArPdX species on the heterogeneous surface. Thus, the ligand-free nanopalladium supported on LDH, synthesized by the simple protocol, displays superior activity over the other heterogeneous catalysts inclusive of nanopalladium in the C-C coupling reactions of chloroarenes.
Activation of CX (=Cl, Br) bond in aryl halides toward the palladium-catalyzed Heck reaction using 2,6-bis(diphenylphosphino)pyridine
Ataei, Ali,Nadri, Shirin,Rafiee, Ezzat,Jamali, Sirous,Joshaghani, Mohammad
, p. 30 - 35 (2013)
The 2,6-bis(diphenylphosphino)pyridine/palladium catalytic system successfully catalyzes the Heck coupling reaction of less reactive aryl chlorides as well as aryl bromides with styrene to give the corresponding olefins in reasonable yields. TBAB (tetrabu
Controlling Multiple Active Sites on Pd?CeO2 for Sequential C?C Cross-coupling and Alcohol Oxidation in One Reaction System
Ko, Wonjae,Kim, Ju Hee,Yim, Guk Hee,Lee, Seong Chan,Kim, Sumin,Kwak, Minjoon,Choi, Hyunwoo,Kim, Jongchan,Antink, Wytse Hooch,Kim, Jiheon,Lee, Chan Woo,Bok, Jinsol,Jung, Yoon,Lee, Eunwon,Lee, Kug-Seung,Cho, Sung-Pyo,Kim, Do Heui,Kim, Young Gyu,Lee, Byoung-Hoon,Hyeon, Taeghwan,Yoo, Dongwon
, (2022/01/22)
Ceria (CeO2)-supported metal catalysts have been widely utilized for various single-step chemical transformations. However, using such catalysts for a multistep organic reaction in one reaction system has rarely been achieved. Here, we investigate multiple active sites on Pd?CeO2 catalysts and optimize them for a multistep reaction of C?C cross-coupling and alcohol oxidation. Atomic-level imaging and spectroscopic studies reveal that metallic Pd0 and Pd?CeO2 interface are active sites on Pd?CeO2 for C?C cross-coupling and oxidation, respectively. These active sites are controlled under the structural evolution of Pd?CeO2 during reductive heat-treatments. Accordingly, we found that optimally reduced Pd?CeO2 catalysts containing ～1.5 nm-sized Pd nanoclusters with both sites in balance are ideal for multistep chemical transformations in one reaction system. Our strategy to design supported metal catalysts leads to one-pot sequential synthetic protocols for pharmaceutical building blocks.
Electrochemical Proton Reduction over Nickel Foam for Z-Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes
Valiente, Alejandro,Martínez-Pardo, Pablo,Kaur, Gurpreet,Johansson, Magnus J.,Martín-Matute, Belén
, (2021/12/22)
Selective reduction strategies based on abundant-metal catalysts are very important in the production of chemicals. In this paper, a method for the electrochemical semihydrogenation and semideuteration of alkynes to form Z-alkenes was developed, using a simple nickel foam as catalyst and H3O+ or D3O+ as sources of hydrogen or deuterium. Good yields and excellent stereoselectivities (Z/E up to 20 : 1) were obtained under very mild reaction conditions. The reaction proceeded with terminal and nonterminal alkynes, and also with alkynes containing easily reducible functional groups, such as carbonyl groups, as well as aryl chlorides, bromides, and even iodides. The nickel-foam electrocatalyst could be recycled up to 14 times without any change in its catalytic properties.
New Bidentate N-Sulfonyl-Substituted Aromatic Amines as Chelate Ligand Backbones: Pd Catalyst Generation in C-C Coupling via in Situ and Precatalyst Modes
Oloyede, Hammed Olawale,Akong Akong, Raymond,Woods, Joseph Anthony Orighomisan,G?rls, Helmar,Plass, Winfried,Eseola, Abiodun Omokehinde
, p. 101 - 110 (2020/07/28)
A series of six new, bidentate ligands based on N-(2-(R-sulfonamido)benzyl)R-sulfonamide have been isolated as dianionic or monoanionic chelators via condensation of 2-(aminomethyl)aniline with sulfonyl chloride reagents; R = methyl (1 and 1′), tolyl (2 and 2′), 2,4,6-Trimethylphenyl (3), or 2,4,6-Triisopropylphenyl (4). Complexes of ligands 2-4 reacted at room temperature with palladium(ii) acetate in the presence of various monodentate N-donor co-ligands to form complexes Pd2(2dmap), Pd2′(OAc.py), Pd3(2acn), Pd3(2py), Pd4(2acn), and Pd4(2py), which were structurally confirmed by three X-ray crystal analyses. Results of catalysis studies in water showed high turnover frequencies and yields of up to 98 % within 10 min and at 0.2 mol-% palladium catalyst loading. Relative to ligand-free catalysis in the presence of only Pd(OAc)2, the ligand-supported palladium species clearly possess positive catalytic advantage. Furthermore, Suzuki coupling efficiencies by 1: 1 'Pd(OAc)2 + ligand' yielded notably better outcomes than for the 1: 2 'Pd(OAc)2 + ligand' in situ catalyst generation, which reveals that coordinative saturation is undesirable. The size of the complementing monodentate co-ligand was observed to influence the catalytic efficiency such that bulkier co-ligands consistently yielded improved turnover frequency values, which leads to the conclusion that steric repulsion between the synthesised ligands and the bulkier co-ligands aided the generation of vacant coordination sites for the more active complexes. Moderate Heck coupling activity was recorded for the complexes and better activities appear to correlate with moderate bulkiness of ligand 3.
N-donor-stabilized Pd(II) species supported by sulphonamide-azo ligands: Ligand architecture, solvent co-ligands, C–C coupling
Oloyede, Hammed Olawale,Orighomisan Woods, Joseph Anthony,G?rls, Helmar,Plass, Winfried,Eseola, Abiodun Omokehinde
, (2019/09/10)
In this report, a series of synthetically affordable phosphine-free ligands (L1 – L4) of the form RSO2–NH–Ph–N[dbnd]N–Ph–NH–SO2R were prepared and examined as organic ligands for stabilizing palladium active centers; R = methyl, tolyl or triiso-propylphenyl. Palladium complexes, which were obtained in varying coordination environments as well as with varying complementary co-ligands (water, acetonitrile or pyridine), have been subjected to Suzuki and Heck coupling experiments in order to study molecular level ligand effects on preferred catalyst settings. The appreciable coupling activities for Suzuki and Heck coupling with functional group tolerance were recorded for palladium species generated from the chelate ligands. Results show that, despite the tridentate chelation characteristics of these azo-benzene ligands, the introduction of bulky units at the sulfonyl groups enabled generation of active palladium species with high turnover frequencies; e.g. 5040 h?1 (84% yield) within 5 min at 0.2 mol % loading of Pd.L2.py in only water as solvent. A correlation between catalytic efficiencies and the bulkiness of the coordinated co-ligand was obtained. However, while Suzuki coupling activity increased with increase in co-ligand sizes of the preformed complexes (i.e. water acetonitrile pyridine), the pyridyl co-ligand turned out to be very unfavourable for Heck coupling where the acetonitrile-complemented complexes possessed the higher activities. Therefore, it could be concluded that the best catalyst setting for Suzuki coupling may not be the best for Heck reaction.
General and Phosphine-Free Cobalt-Catalyzed Hydrogenation of Esters to Alcohols
Shao, Zhihui,Zhong, Rui,Ferraccioli, Raffaella,Li, Yibiao,Liu, Qiang
supporting information, p. 1125 - 1130 (2019/10/22)
Catalytic hydrogenation of esters is essential for the sustainable production of alcohols in organic synthesis and chemical industry. Herein, we describe the first non-noble metal catalytic system that enables an efficient hydrogenation of non-activated esters to alcohols in the absence of phosphine ligands (with a maximum turnover number of 2391). The general applicability of this protocol was demonstrated by the high-yielding hydrogenation of 39 ester substrates including aromatic/aliphatic esters, lactones, polyesters and various pharmaceutical molecules.
