Chiral N-Oxides as Catalysts or Ligands in Enantioselective Reactions

Nakajima, Makoto

doi:10.5059/yukigoseikyokaishi.61.1081

Cited by 20 publications

(3 citation statements)

References 3 publications

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“…The biquinoline N , N '‐dioxides were further extended as chiral ligands for enantioselective reactions. [ 10‐11 ]…”

Section: Initial Discoverymentioning

confidence: 99%

Feng Ligand: Privileged Chiral Ligand in Asymmetric Catalysis

Wang

2021

Chin. J. Chem.

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Feng ligand | N,N'-Dioxide | O ligands | Asymmetric catalysis | Lewis acids Catalysts and ligands possessing the great ability to tolerate over a wide range of mechanistically unrelated reactions are remarked as "privileged", which are rather scarce but extremely meaningful in asymmetric catalysis. Feng and co-workers have developed a library of conformationally flexible, C 2-symmetric N,N'-dioxide amide compounds with original design and featured structure (named as Feng ligand now). They were initially reported as chiral organocatalysts in 2005 and have been further developed as a new class of privileged chiral ligands since 2006. Tremendous success, including versatile coordination chemistry with plenty of metal sources (main-group metals, transition metals, and rare-earth metals), a truly broad scope of asymmetric reactions (more than 50 types), diverse areas of catalysis (organocatalysis, Lewis-acid catalysis, bimetallic relay catalysis, and photocatalysis), numerous synthetic applications of bioactive compounds, has been achieved using Feng N,N'-dioxide. Besides, they demonstrate that chiral ligands with conformationally flexible property can offer excellent chiral environment as well, which challenges the conventional idea preferring rigid structures in the design of chiral ligands. Herein, we briefly introduced the discovery of Feng ligand and the millstones during the development. We also covered the successful applications of Feng ligand by other scientists as well as novel chiral ligands inspired by them. Contents 1. Introduction 969 2. Initial Discovery 970 3. Representative Applications 971 3.1. Classical asymmetric reactions 971 3.2. Novel asymmetric reactions 975 4. Studies by Other Groups 977 4.1. Reactions using Feng ligand 977 4.2. Novel chiral ligands inspired by Feng ligand 980 5. Conclusions 980

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“…The biquinoline N , N '‐dioxides were further extended as chiral ligands for enantioselective reactions. [ 10‐11 ]…”

Section: Initial Discoverymentioning

confidence: 99%

Feng Ligand: Privileged Chiral Ligand in Asymmetric Catalysis

Wang

2021

Chin. J. Chem.

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“…Over the past decade, relatively little attention has been paid to the use of chiral heteroaromatic N-oxides as ligands for metal complexes catalyzed reactions. Several mentions come from 2002-2003 and include (S)-1-CdI 2 complex as a catalyst for conjugate addition of thiol to enone or enal, providing 70-78% ee [62], and (R)-1-Sc(OTf) 3 complex as a catalyst for Michael addition of β-keto ester to methyl vinyl ketone or acrolein, giving almost quantitative yield with moderate enantioselectivity of 38-84% ee [48]. Chiral copper (II)-terpyridine mono-N-oxide and di-N-oxide complexes were used in asymmetric cyclopropanation of styrene [63].…”

Section: Chiral Heteroaromatic N-oxides As Ligands For Metal Catalysismentioning

confidence: 99%

Heteroaromatic N-Oxides in Asymmetric Catalysis: A Review

Wrzeszcz

Siedlecka

2020

Molecules

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An increasing interest in the synthesis and use of optically active pyridine N-oxides as chiral controllers for asymmetric reactions has been observed in the last few years. Chiral heteroaromatic N-oxides can work as powerful electron-pair donors, providing suitable electronic environments in the transition state formed within the reaction. The nucleophilicity of the oxygen atom in N-oxides, coupled with a high affinity of silicon to oxygen, represent ideal properties for the development of synthetic methodology based on nucleophilic activation of organosilicon reagents. The application of chiral N-oxides as efficient organocatalysts in allylation, propargylation, allenylation, and ring-opening of meso-epoxides, as well as chiral ligands for metal complexes catalyzing Michael addition or nitroaldol reaction, can also be found in the literature. This review deals with stereoselective applications of N-oxides, and how the differentiating properties are correlated with their structure. It contains more recent results, covering approximately the last ten years. All the reported examples have been divided into five classes, according to the chirality elements present in their basic molecular frameworks.

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“…Nakajima and co‐workers designed axially dissymmetric dioxides, 1,1′‐biisoquinoline N , N′ ‐dioxide ( 4 ), which was patterned after BINOL, and 3,3′‐dimethyl‐2,2′‐biquinoline N , N′ ‐dioxide ( 5 ), in which the N ‐oxide moieties are embedded within a chiral pocket created by the walls of the biaryl unit (Figure 3). 3e…”

Section: Planar Axial and Central Chiral Pyridine N‐oxide Catalystsmentioning

confidence: 99%

Helical Chiral Pyridine N‐Oxides: A New Family of Asymmetric Catalysts

Chen

Takenaka

2009

Chemistry A European J

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Optically active chiral alkyl chlorides are valuable compounds because of their bioactivity and versatile synthetic utility. Accordingly, the ring opening of epoxides with a chloride nucleophile stands as an important goal in asymmetric catalysis. We describe herein recent advances in the design and development of chiral pyridine N-oxide catalysts for the enantioselective synthesis of chlorohydrins.

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Chiral N-Oxides as Catalysts or Ligands in Enantioselective Reactions

Cited by 20 publications

References 3 publications

Feng Ligand: Privileged Chiral Ligand in Asymmetric Catalysis

Feng Ligand: Privileged Chiral Ligand in Asymmetric Catalysis

Heteroaromatic N-Oxides in Asymmetric Catalysis: A Review

Helical Chiral Pyridine N‐Oxides: A New Family of Asymmetric Catalysts

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