Reactivity Umpolung of the C═N Bond in Quinoxaline Scaffold Enabling Direct Nucleophilic Attack of Alkyl Grignard Reagents at the N-Terminus

Peng, Yun; Chen, Lailin; Bao, Hanyang; Zhou, Bingwei; Wu, Huayue; Liu, Yunkui

doi:10.1021/acs.orglett.2c01385

Cited by 5 publications

(1 citation statement)

References 36 publications

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“…Ground state (triplet) O

is also used as an oxidant for many synthetic pathways (see, for example, Refs. [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ] and references therein) as it is a very abundant and environmentally friendly reagent. To circumvent the limitation imposed by the spin-forbidden characters of these reactions, most of them use metal centers as catalyzers.…”

Section: Introductionmentioning

confidence: 99%

Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates—Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid

Ortega

Gil‐Guerrero

González-Sánchez

et al. 2023

IJMS

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The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.

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“…Ground state (triplet) O

Section: Introductionmentioning

confidence: 99%

Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates—Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid

Ortega

Gil‐Guerrero

González-Sánchez

et al. 2023

IJMS

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H‐Bond Donor‐Directed Switch of Diastereoselectivity in the Enantioselective Intramolecular Aza‐Henry Reaction of Ketimines

Tian,

Yi‐Gong,

et al. 2024

Chemistry A European J

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We report an H‐bond donor controlled diastereoselective switchable intramolecular aza‐Henry reaction of ketimines derived from α‐ketoesters and 2‐(2‐nitroethyl)anilines, allowing facile access to chiral tetrahydroquinolines bearing an aza‐quaternary carbon stereocenter, which are privileged scaffold for medicinal researches. While newly developed cinchona alkaloid derived phosphoramide‐bearing quaternary ammonium salt C2 selectively give cis‐adducts in up to 20:1 dr and 99% ee, the corresponding urea‐bearing analogue C8 preferentially give trans‐adducts in up to 20:1 dr and 99% ee.

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Synthesis of 3‐Arylquinoxalin‐2(1H)‐ones under Visible‐Light Irradiation with Oxygen‐Doped Carbon Nitride as Heterogenous Photocatalyst

et al. 2023

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A novel oxygen‐doped graphitic carbon nitride (OCN) material was designed and synthesized via the hydrothermal‐calcination method with melamine and hydroperoxide as starting materials. The OCN material was utilized as a highly efficient solid metal‐free photocatalyst for the synthesis of 3‐arylquinoxalin‐2(1H)‐ones via the catalytic decomposition of aryl diazonium salts under blue light irradiation. Following this approach, various 3‐arylquinoxalin‐2(1H)‐one derivatives could be obtained in moderate to excellent yields with broad substrate scope under mild conditions. Also, the OCN solid photocatalyst shows good recyclability in the reaction, there was no appreciable loss in yields observed even after 5 cycles. This methodology offers a practical, mild, and metal‐free alternative to the preparation of 3‐arylquinoxalin‐2(1H)‐ones.

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Reactivity Umpolung of the C═N Bond in Quinoxaline Scaffold Enabling Direct Nucleophilic Attack of Alkyl Grignard Reagents at the N-Terminus

Cited by 5 publications

References 36 publications

Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates—Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid

Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates—Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid

H‐Bond Donor‐Directed Switch of Diastereoselectivity in the Enantioselective Intramolecular Aza‐Henry Reaction of Ketimines

Synthesis of 3‐Arylquinoxalin‐2(1H)‐ones under Visible‐Light Irradiation with Oxygen‐Doped Carbon Nitride as Heterogenous Photocatalyst

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