Efficient Catalytic Enantioselective Hydroxyamination of α‐Aryl‐α‐Cyanoacetates with 2‐Nitrosopyridines

Jingchuan, Zhang; Fang, Kai; Lin, Lili; Lü, Yan; Liu, Xiaohua; Feng, Xiaoming

doi:10.1002/chem.201800592

Cited by 5 publications

(2 citation statements)

References 103 publications

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“…In particular, we decided to examine the use of tertiary α-halonitriles as electrophiles so as to produce α-disubstituted α-aminonitriles. Whereas catalytic enantioselective Strecker reactions of aldimines provide a versatile approach to the synthesis of enantioenriched α-monosubstituted α-aminonitriles, , the corresponding reactions of ketimines to afford α-disubstituted α-aminonitriles are less well-developed. − …”

Section: Resultsmentioning

confidence: 99%

Photoinduced, Copper-Catalyzed Enantioconvergent Alkylations of Anilines by Racemic Tertiary Electrophiles: Synthesis and Mechanism

et al. 2022

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Transition-metal catalysis of substitution reactions of alkyl electrophiles by nitrogen nucleophiles is beginning to emerge as a powerful strategy for synthesizing higher-order amines, as well as controlling their stereochemistry. Herein, we report that a readily accessible chiral copper catalyst (commercially available components) can achieve the photoinduced, enantioconvergent coupling of a variety of racemic tertiary alkyl electrophiles with aniline nucleophiles to generate a new C−N bond with good ee at the fully substituted stereocenter of the product; whereas this photoinduced, copper-catalyzed coupling proceeds at −78 °C, in the absence of light and catalyst, virtually no C−N bond formation is observed even upon heating to 80 °C. The mechanism of this new catalytic enantioconvergent substitution process has been interrogated with the aid of a wide array of tools, including the independent synthesis of proposed intermediates and reactivity studies, spectroscopic investigations featuring photophysical and EPR data, and DFT calculations. These studies led to the identification of three copperbased intermediates in the proposed catalytic cycle, including a chiral three-coordinate formally copper(II)−anilido (DFT analysis points to its formulation as a copper(I)−anilidyl radical) complex that serves as a persistent radical that couples with a tertiary organic radical to generate the desired C−N bond with good enantioselectivity.

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Section: Resultsmentioning

confidence: 99%

Photoinduced, Copper-Catalyzed Enantioconvergent Alkylations of Anilines by Racemic Tertiary Electrophiles: Synthesis and Mechanism

et al. 2022

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“…Inspired by the abovementioned strategies, in 2018, Feng and co-workers performed the organocatalytic hydroxyamination of α-substituted α-cyanoacetates with nitrosobenzene 55 . Previously, while excellent reactivity was achieved, a strong background reaction hampered enantioselectivity (22-59% ee ), which became apparent when the Jørgensen group achieved nearly the full conversion at −78 °C within 5 h 56 .…”

Section: Synthesis Of αα-Disubstituted α-Aas Via C-n Bond Formationmentioning

confidence: 99%

Challenges and recent advancements in the synthesis of α,α-disubstituted α-amino acids

Zhang,

Vanderghinste,

Wang

et al. 2024

Nat Commun

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Abstractα,α-Disubstituted α-amino acids (α-AAs) have improved properties compared to other types of amino acids. They serve as modifiers of peptide conformation and as precursors of bioactive compounds. Therefore, it has been a long-standing goal to construct this highly valuable scaffold efficiently in organic synthesis and drug discovery. However, access to α,α-disubstituted α-AAs is highly challenging and largely unexplored due to their steric constraints. To overcome these, remarkable advances have been made in the last decades. Emerging strategies such as synergistic enantioselective catalysis, visible-light-mediated photocatalysis, metal-free methodologies and CO2 fixation offer new avenues to access the challenging synthesis of α,α-disubstituted α-AAs and continuously bring additional contributions to this field. This review article aims to provide an overview of the recent advancements since 2015 and discuss existing challenges for the synthesis of α,α-disubstituted α-AAs and their derivatives.

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Cyanation of glycine derivatives

Liang

Bao

et al. 2021

Chem. Commun.

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Efficient Catalytic Enantioselective Hydroxyamination of α‐Aryl‐α‐Cyanoacetates with 2‐Nitrosopyridines

Cited by 5 publications

References 103 publications

Photoinduced, Copper-Catalyzed Enantioconvergent Alkylations of Anilines by Racemic Tertiary Electrophiles: Synthesis and Mechanism

Photoinduced, Copper-Catalyzed Enantioconvergent Alkylations of Anilines by Racemic Tertiary Electrophiles: Synthesis and Mechanism

Challenges and recent advancements in the synthesis of α,α-disubstituted α-amino acids

Cyanation of glycine derivatives

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