Eine neuartige und stereospezifische Aziridinierung von Alkenen mit einem chiralen Nitridomangankomplex

Minakata, Satoshi; Ando, Takehiro; Nishimura, Masaaki; Ryu, Ilhyong; Komatsu, Mitsuo

doi:10.1002/(sici)1521-3757(19981217)110:24<3596::aid-ange3596>3.3.co;2-x

Cited by 3 publications

(4 citation statements)

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“…Subsequent works by Carreira and co‐workers demonstrate that several nitrido manganese Schiff base complexes can be activated with TFAA and undergo NCOCF 3 group transfer with silyl enol ethers, glycols, and styrene to afford amination or aminohydroxylation products 8b–e. Recently, Komatsu and co‐workers reported asymmetric aziridination of alkenes and asymmetric amination of silyl enol ether with chiral nitrido manganese Schiff base complexes upon ( p ‐MeC 6 H 4 SO 2 ) 2 O or TFAA activation 8f…”

Section: Methodsmentioning

confidence: 99%

Nitrido Ruthenium Porphyrins: Synthesis, Characterization, and Amination Reactions with Hydrocarbon or Silyl Enol Ethers

Leung¹,

Huang²,

Liang³

et al. 2003

Angew Chem Int Ed

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Ruthenium porphyrins constitute an unmatched family of metalloporphyrin that exhibits extraordinary versatility in binding N-donating ligands at the axial sites. [1±5] A wide variety of ruthenium porphyrins featuring axial RuÀN bonds have been prepared, including those bearing amine, [1c, 3a,3b] amido, [3b±d,g] imido, [3a,c±e,g,j] imine, [3h, 4] methyleneamido, [3h] nitrile, [1a, 2] hydrazido, [3f] nitrosoarene, [1b, 3i] nitrosyl, [5] and dinitrogen [1d] axial ligands (Scheme 1, a±j). This makes the lack of [*] Prof.

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Section: Methodsmentioning

confidence: 99%

Nitrido Ruthenium Porphyrins: Synthesis, Characterization, and Amination Reactions with Hydrocarbon or Silyl Enol Ethers

Leung¹,

Huang²,

Liang³

et al. 2003

Angew Chem Int Ed

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“…Manganese(V) imido complexes have been postulated as active intermediates in many useful organic transformation reactions . For instance, manganese(V) nitrido complexes with porphyrin or salen ligands react with trifluoroacetic anhydride (TFAA) to generate manganese(V) acylimido species, which can transfer the CF 3 CON group to alkenes .…”

Section: Methodsmentioning

confidence: 99%

“…For instance, manganese(V) nitrido complexes with porphyrin or salen ligands react with trifluoroacetic anhydride (TFAA) to generate manganese(V) acylimido species, which can transfer the CF 3 CON group to alkenes . p ‐Toluenesulfonic anhydride is also used to convert chiral managnese(V) salen nitrido complexes to imido species, which can perform asymmetric aziridination of alkenes . Trifluoroacetic acid and BF 3 have also been employed to convert manganese(V) salen nitrido complexes to imido species, which can react with alkenes to give the parent aziridines .…”

Section: Methodsmentioning

confidence: 99%

Generation and Reactivity of a One‐Electron‐Oxidized Manganese(V) Imido Complex with a Tetraamido Macrocyclic Ligand

Shi

Xie

Lam

et al. 2019

Chemistry A European J

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“…was analyzed (Figure 4). 18 In this case, the reaction of styrene results in a significantly lower enantiomeric ratio than that resulting from substrates with substitution trans in the β position. An excellent correlation of the size of the group in the β position of the styrene is observed with ψ=1.4.…”

Section: Systematic Evaluation Of Proline Carbamate Ligands In Nozakimentioning

confidence: 99%

Quantitatively Correlating the Effect of Ligand‐Substituent Size in Asymmetric Catalysis Using Linear Free Energy Relationships

Miller¹,

Sigman²

2008

Angew Chem Int Ed

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In the past three decades, the discovery and application of effective asymmetric catalysts has flourished in both academic and industrial settings.[1] This is especially true within the recent decade where the field of asymmetric catalysis has witnessed an incredible expansion, and the benchmarks for acceptable asymmetric induction have significantly risen. However, the approach to catalyst identification remains mainly empirical, wherein evaluation of a considerable number of catalyst structures is required to develop a mature chiral catalyst. While this process has been expedited by technological advancements, [2] the understanding of the relationship between catalyst structure and the enantioselectivity of the catalyzed reaction is generally precarious. This can be attributed to the small energy differences in the activation barrier leading to the enantiomeric products and/or the complicated preequilibria in most catalytic reactions. [3] An approach to developing greater predictive power in asymmetric catalysis is based on the use of modular ligands [4] in lieu of a detailed understanding of the microscopic processes involved in asymmetric induction. We believe the ability to make systematic changes to the ligand structure not only leads to enhanced product enantiomeric excess, [5] but allows for the elucidation of structure-enantioselectivity relationships. [6] Herein, we report the use of a modular ligand set to systematically study the effect of ligand size and the first observation of a linear free energy relationship between steric parameters and enantiomeric ratio. Additionally, our analysis of several previously reported enantioselective reactions reveals similar linear free energy relationships.We have recently disclosed the use of modular oxazoline ligands [7] in enantioselective Nozaki-Hiyama-Kishi reactions of allylic halides [8,9] with both aldehydes [5a] and ketones [5c] ( Figure 1). A key observation from these studies is that the facial selectivity of the reaction is directly correlated to the absolute configuration of the proline module of the ligand. For example, in comparing ligands 1 a and 1 b, which differ only in the configuration of the proline module, a considerable difference in enantiomeric ratio is observed for allylation of both aldehydes and ketones. Most notably, the allylation of benzaldehyde is promoted in nearly 90 % ee (96:4 e.r. and 94.5:5.5 e.r.) using both ligands but with different senses of asymmetric induction. A similar effect is also found for the allylation of acetophenone. Systematic changes to the configuration of the other chiral centers in the ligand structure had only a subtle impact. These observations prompted us to explore the role of the proline module in greater detail. In order to initiate the investigation, we decided to make systematic changes to the proline module and probe the effect on the enantioselective outcome of the reaction. This was reasoned to be most easily accomplished through modification of the proline nitrogen, as proline carbamates...

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Eine neuartige und stereospezifische Aziridinierung von Alkenen mit einem chiralen Nitridomangankomplex

Cited by 3 publications

References 0 publications

Nitrido Ruthenium Porphyrins: Synthesis, Characterization, and Amination Reactions with Hydrocarbon or Silyl Enol Ethers

Nitrido Ruthenium Porphyrins: Synthesis, Characterization, and Amination Reactions with Hydrocarbon or Silyl Enol Ethers

Generation and Reactivity of a One‐Electron‐Oxidized Manganese(V) Imido Complex with a Tetraamido Macrocyclic Ligand

Quantitatively Correlating the Effect of Ligand‐Substituent Size in Asymmetric Catalysis Using Linear Free Energy Relationships

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