Die N‐H‐Funktion in der metallorganischen Katalyse

Zhao, Baoguo; Han, Zhaobin; Ding, Kuiling

doi:10.1002/ange.201204921

Cited by 71 publications

(5 citation statements)

References 494 publications

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“…When 2 was treated with two equivalents of a base under H 2 or in 2-propanol, the hydrido complex 4 containing protic NHC and pyrazolato groups was obtained through metal-ligand cooperation.Proton-responsive ligands surrounding a metal play crucial roles in metal-ligand bifunctional catalysis. [1] A variety of protic ligands, such as amines, [2,3] pyrazoles, [4][5][6][7][8][9] imidazoles, [10] oximes, [11, 12] pyridinols, [13] and picoline/lutidine-based chelates, [14] have been used to facilitate the substrate binding, activation, and transformation through noncovalent interactions. Although most of the artificial bifunctional catalysts have only one kind of such protic ligands, metalloenzymes in Nature generally possess two or more structurally differentiated cooperating groups with various ranges of proton affinity in the second coordination sphere, which accelerate biological transformations in a delicate manner.…”

mentioning

confidence: 99%

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Toda

Kuwata

Ikariya

2014

Chemistry A European J

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A reaction of a 2-(imidazol-1-yl)methyl-6-(pyrazol-3-yl)pyridine with [RuCl2 (PPh3 )3 ] resulted in tautomerization of the imidazole unit to afford the unsymmetrical pincer-type ruthenium complex 2 containing a protic pyrazole and N-heterocyclic carbene (NHC) arms. Deprotonation of 2 with one equivalent of a base led to the formation of the NHC-pyrazolato complex 3, indicating that the protic NHC arm is less acidic. When 2 was treated with two equivalents of a base under H2 or in 2-propanol, the hydrido complex 4 containing protic NHC and pyrazolato groups was obtained through metal-ligand cooperation.

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confidence: 99%

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Toda

Kuwata

Ikariya

2014

Chemistry A European J

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“…In analogy to the activity displayed by Noyori's complex and related reversible amido-to-amino switchable ligands, [7] we were curious as to whether the combination of a Lewis acidic metal and a Brønsted basic ligand would result in direct heterolytic H 2 cleavage. It should be noted that there is a pronounced difference in both Ru-amide geometry (equatorial/meridional versus piano-stool) and Ru-amide character (inner-sphere coordination versus two-bond separation), which might have pronounced differences for amide protonolysis.…”

Section: Heterolytic Splitting Of Dihydrogenmentioning

confidence: 99%

“…[4] Proton-responsive ligands can also be used for "hydrogen-borrowing" reactions wherein the substrate is dehydrogenated by the catalyst, undergoes a coupling reaction, and is then hydrogenated. [5] The proton-responsive feature might involve temporary dearomatization of functionalized pyridines, [6] the interconversion between amino/amido units within the ligand framework, [7] or pH-responsive pyridonate fragments. [8] In addition, some other concepts have been explored as well.…”

Section: Introductionmentioning

confidence: 99%

“…Only the major conformation of the disordered n-butyl chain is shown. Selected bond lengths [Å] and angles [°]: Ru-P1 2.3096(4), Ru-P2 2.3466(4), Ru-O1 2.1485(11), Ru-C17 1.8293(16), Ru-Cl 2.4673(4), P1-N 1.6597(14), N-S 1.5435(14), S-O1 1.4911(13), S-O2 1.4416(14); P1-Ru-P2 100.15(2), P1-Ru-Cl 168.320(14), P2-Ru-Cl 86.773(14), O1-Ru-C17 174.02(5), P1-Ru-O1 82.39(3), P2-Ru-O1 93.54(3), N-S-O1 112.92(7), N-S-O2 113.44(8), Ru-C17-O3 176.64(14), P-N-S 119.30(9). Symmetry operation i: -x, y, 0.5z.…”

mentioning

confidence: 99%

“…Selected bond lengths [Å] and angles [°] for 11: Ru-P 2.2637(3), Ru-O1 2.1210(10), Ru-N2 2.0200(13), Ru-N3 1.9991(13), Ru-N4 2.0175(12), Ru-N5 2.1248(13), P-N1 1.6720(12), N1-S 1.5544(12), S-O1 1.4996(10), S-O2 1.4482(10); P-Ru-O1 83.87(3), P-Ru-N2 93.27(4), P-Ru-N3 96.87(4), P-Ru-N5 171.22(4), N2-Ru-N4 175.11(5), O1-Ru-N3 178.70(4), P-N1-S 116.65(7), N1-S-O1 112.65(6), N1-S-O2 112.05(6), Ru-O1-S 117.44(6), Ru-N2-C20 174.81(15). For 13: Ru-P 2.3230(6), Ru-O1 2.1334(16), Ru-N2 2.0112(19), P-N1 1.671(2), N1-S 1.552(2), S-O1 1.4978(18), S-O2 1.4387(19); P-Ru-O1 81.31(5), P-Ru-N2 90.41(6), PЈ-Ru-O1 98.69(5), O1-Ru-N2 89.55(7), P-N1-S 115.40(13), N1-S-O1 113.36(11), N1-S-O2 113.00(12), Ru-O1-S 118.55(9). Symmetry operation i: 1x, 1y, 1z.…”

mentioning

confidence: 99%

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Synthesis, Coordination Chemistry, and Cooperative Activation of H₂ with Ruthenium Complexes of Proton‐Responsive METAMORPhos Ligands

et al. 2013

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The synthetic scope of proton-responsive sulfonamidophosphorus (METAMORPhos) ligands is expanded and design principles for the selective formation of particular tautomers, ion pairs, or double condensation products are elucidated. These systems have been introduced in the coordination sphere of Ru for the first time, thereby enabling the exclusive coordination as a monoanionic P,O chelate. Depending on the Ru precursor, halide-bridged dinuclear species 3-5 or cymene-derived piano-stool complexes 6-9 are isolated. The METAMORPhos framework is shown to play a role in the heterolytic cleavage of H 2 , with species 7 converted into neu- [a] van '1826 tral monohydride 10. Substitution chemistry with cymene complex 7 has also been examined, thereby giving rise to tetrakis(acetonitrile) adduct 11. Introduction of a second equivalent of METAMORPhos ligand to this species yielded the bis(ligated) derivative 13, for which variable-temperature (VT) NMR spectroscopy indicates coalescence of the phosphine donors at high temperature. Solid-state structures of 3, 6, 11, and 13 are presented to establish the precise bonding situation of the inorganic PNSO framework within METAMORPhos upon coordination as a proton-responsive monoanionic P,O chelate.

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Asymmetric Hydrogenation of β‐Keto Sulfonamides and β‐Keto Sulfones with a Chiral Cationic Ruthenium Diamine Catalyst

et al. 2013

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Optically active β‐hydroxy sulfonamides and β‐hydroxy sulfones are very important building blocks for the preparation of bioactive compounds and pharmaceuticals. In this work, a highly efficient asymmetric hydrogenation of β‐keto sulfonamides and β‐keto sulfones has been developed using the phosphine‐free chiral ruthenium complex Ru(OTf)(TsDPEN)(η6‐p‐cymene) as the catalyst, to afford the corresponding β‐hydroxy sulfonamides and β‐hydroxy sulfones in high yields with excellent optical purities. In addition, a cascade asymmetric hydrogenation/dynamic kinetic resolution (DKR) of racemic cyclic β‐keto sulfonamides and β‐keto sulfones was also realized using the same catalyst, to give the corresponding chiral cyclic β‐hydroxy sulfonamides and β‐hydroxy sulfones in good yields with excellent enantio‐ and diastereoselectivities.magnified image

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Die N‐H‐Funktion in der metallorganischen Katalyse

Cited by 71 publications

References 494 publications

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Synthesis, Coordination Chemistry, and Cooperative Activation of H₂ with Ruthenium Complexes of Proton‐Responsive METAMORPhos Ligands

Asymmetric Hydrogenation of β‐Keto Sulfonamides and β‐Keto Sulfones with a Chiral Cationic Ruthenium Diamine Catalyst

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Die N‐H‐Funktion in der metallorganischen Katalyse

Cited by 71 publications

References 494 publications

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

Synthesis, Coordination Chemistry, and Cooperative Activation of H2 with Ruthenium Complexes of Proton‐Responsive METAMORPhos Ligands

Asymmetric Hydrogenation of β‐Keto Sulfonamides and β‐Keto Sulfones with a Chiral Cationic Ruthenium Diamine Catalyst

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Synthesis, Coordination Chemistry, and Cooperative Activation of H₂ with Ruthenium Complexes of Proton‐Responsive METAMORPhos Ligands