Asymmetric Nanocatalysis: N‐Heterocyclic Carbenes as Chiral Modifiers of Fe<sub>3</sub>O<sub>4</sub>/Pd nanoparticles

Ranganath, Kalluri V. S.; Kloesges, Johannes; Schäfer, Andreas; Glorius, Frank

doi:10.1002/anie.201002782

Cited by 316 publications

(202 citation statements)

References 78 publications

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“…General procedure for the preparation of imidazolinium halides [21,22] An amino alcohol and dibromoethane in the molar ratio of 2:1 were placed in an autoclave under nitrogen atmosphere. The autoclave was closed and the reaction mixture was heated at …”

Section: Methodsmentioning

confidence: 99%

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Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

Morel

Trzeciak

2016

Fr. Ukr. J. Chem.

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Palladium anionic complexes with imidazolinium cations containing hydroxyl substituents were used as catalyst precursors in the Suzuki-Miyaura and the Heck cross-coupling.High activity of anionic complexes was noted in the Suzuki-Miyaura reaction of 2-bromotoluene with phenylboronic acid at 40 o C in 2-propanol and a 2-propanol/water mixture using conventional heating or microwaves. Similarly, bromonaphtalene and iodonaphtalene reacted efficiently with naphtylboronic acid and 4-methylnaphtylboronic acid. A remarkably lower activity was noted when anionic palladium complexes were employed in the Heck coupling of 2,3-dihydrofuran withiodobenzene. An increase in conversion in the Heck reaction was achieved when Pd(OAc)2 was used as a catalyst precursor together with imidazolinium salts as co-catalysts. ________________________________________________________________________________

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Section: Methodsmentioning

confidence: 99%

“…asymmetric arylation of 2-methyl-1-tetralone [21] and in the enantioselective addition of Et2Zn to aldehydes [22].…”

mentioning

confidence: 99%

Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

Morel

Trzeciak

2016

Fr. Ukr. J. Chem.

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“…For example, Li and coworkers recently attained enantioselective hydrogenation (96 % ee) of α -ketoesters using chirally modifi ed Pt nanoparticles encapsulated inside CNTs, in which the high activity and enantioselectivity were attributed to the unique 1D nanochannels of the CNTs as the nanochannels readily enrich both the chiral modifi er and the reactants [126] . Another example is that Pd nanoparticles modifi ed by a chiral N -heterocyclic carbene were demonstrated to catalyze asymmetric α -arylations at up to 85 % ee [127] . In contrast with the type I chiral nanoparticles, recent research has obtained a new type of chiral nanoparticles (referred to type II chiral nanoparticles), which exhibits intrinsic chirality in the metal core, such as the chiral arrangement of gold atoms in the 38-atom (Au 38 ) nanoparticles capped by thiolate ligands [128] .…”

Section: Chiral Catalysismentioning

confidence: 99%

The impacts of nanotechnology on catalysis by precious metal nanoparticles

Jin

2012

Nanotechnology Reviews

140

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This review article focuses on the impacts of recent advances in solution phase precious metal nanoparticles on heterogeneous catalysis. Conventional nanometal catalysts suffer from size polydispersity. The advent of nanotechnology has signifi cantly advanced the techniques for preparing uniform nanoparticles, especially in solution phase synthesis of precious metal nanoparticles with excellent control over size, shape, composition and morphology, which have opened up new opportunities for catalysis. This review summarizes some recent catalytic research by using well-defi ned nanoparticles, including shape-controlled nanoparticles, high index-faceted polyhedral nanocrystals, nanostructures of different morphology (e.g., coreshell, hollow, etc.), bi-and multi-metallic nanoparticles, as well as atomically precise nanoclusters. Such well-defi ned nanocatalysts provide many exciting opportunities, such as identifying the types of active surface atoms (e.g., corner and edge atoms) in catalysis, the effect of surface facets on catalytic performance, and obtaining insight into the effects of size-induced electron energy quantization in ultra-small metal nanoparticles on catalysis. With well-defi ned metal nanocatalysts, many fundamentally important issues are expected to be understood much deeper in future research, such as the nature of the catalytic active sites, the metalsupport interactions, the effect of surface atom arrangement, and the atomic origins of the structure-activity and the structure-selectivity relationships.

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“…[6][7][8][9][10][11] However, the equally important enantioselective hydrogenation of α,β-unsaturated carboxylic acids was less studied. [12,13] Chirally modified palladium catalysts, which were used in various enantioselective reactions, [14][15][16][17] were shown to be effective for enantioselective hydrogenation of aryl-substituted α,β-unsaturated carboxylic acids with the ee values of more than 90%. [18][19][20] Aryl substituent in the β-position of the substrate stabilized the reaction intermediates on Pd surface by preventing their isomerization.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Hydrogenation of α,β-Unsaturated Carboxylic Acids：Effects of Palladium Particle Size and Support Acidic Property

陈春辉¹,

展恩胜²,

李勇³

et al. 2013

Acta Chim. Sinica

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Effects of Pd particle size and support acidity on enantioselective hydrogenation of α,β-unsaturated carboxylic acids were systematically studied using Pd nanoparticles with different size immobilized on various oxides. Small Pd particles showed higher activity in the hydrogenation of (E)-2-methyl-2-pentenoic acid due to the larger fraction of edge sites which were more active in olefin hydrogenation; but they did not change the reaction mechanism and/or the adsorption mode of reaction intermediates. Similar correlations in the hydrogenation of (E)-2-methyl-2-butenoic acid and 2-acetamidoacrylic acid further confirmed that the size of Pd particles only mediated the activity but did not alter the enantioselectivity. On the other hand, the activity and the enantioselectivity were strongly dependent on the acidity of the support. The TOF and the ee value followed the order TiO 2 ＞γ-Al 2 O 3 ＞SiO 2 ＞CeO 2 , suggesting that the acidic support favored the adsorption of the reaction intermediates.

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Asymmetric Nanocatalysis: N‐Heterocyclic Carbenes as Chiral Modifiers of Fe₃O₄/Pd nanoparticles

Cited by 316 publications

References 78 publications

Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

The impacts of nanotechnology on catalysis by precious metal nanoparticles

Enantioselective Hydrogenation of α,β-Unsaturated Carboxylic Acids：Effects of Palladium Particle Size and Support Acidic Property

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Asymmetric Nanocatalysis: N‐Heterocyclic Carbenes as Chiral Modifiers of Fe3O4/Pd nanoparticles

Cited by 316 publications

References 78 publications

Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

Effect of imidazolinium salts bearing hydroxy substituents on palladium-catalysed Suzuki–Miyaura and Heck coupling reactions

The impacts of nanotechnology on catalysis by precious metal nanoparticles

Enantioselective Hydrogenation of α,β-Unsaturated Carboxylic Acids：Effects of Palladium Particle Size and Support Acidic Property

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Asymmetric Nanocatalysis: N‐Heterocyclic Carbenes as Chiral Modifiers of Fe₃O₄/Pd nanoparticles