Synthesis of 2-Isoxazoline N-Oxides by Copper-Mediated Radical Annulation of Alkenes with α-Nitrobenzyl Bromides

Masayuki Iwasaki; Yuichi Ikemoto; Yasushi Nishihara

doi:10.1021/acs.orglett.0c02781

Synthesis of 2-Isoxazoline N-Oxides by Copper-Mediated Radical Annulation of Alkenes with α-Nitrobenzyl Bromides

Masayuki Iwasaki, Yuichi Ikemoto, Yasushi Nishihara

Research Institute for Interdisciplinary Science

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

Copper-mediated [3 + 2] annulation of alkenes with α-nitrobenzyl bromides has been developed. The reaction is promoted simply by a copper salt to produce the corresponding 2-isoxazoline N-oxides with perfect regioselectivity. The present method can be conducted under mild conditions, affording a diverse array of 2-isoxazoline N-oxides. The obtained products can readily be converted to the related heterocycles such as 2-isoxazoline and isoxazole. A radical-polar crossover pathway initiated by single-electron transfer from nitronate to a copper salt is proposed.

Original language	English
Pages (from-to)	7577-7580
Number of pages	4
Journal	Organic Letters
Volume	22
Issue number	19
DOIs	https://doi.org/10.1021/acs.orglett.0c02781
Publication status	Published - Oct 2 2020

ASJC Scopus subject areas

Biochemistry
Physical and Theoretical Chemistry
Organic Chemistry

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10.1021/acs.orglett.0c02781

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title = "Synthesis of 2-Isoxazoline N-Oxides by Copper-Mediated Radical Annulation of Alkenes with α-Nitrobenzyl Bromides",

abstract = "Copper-mediated [3 + 2] annulation of alkenes with α-nitrobenzyl bromides has been developed. The reaction is promoted simply by a copper salt to produce the corresponding 2-isoxazoline N-oxides with perfect regioselectivity. The present method can be conducted under mild conditions, affording a diverse array of 2-isoxazoline N-oxides. The obtained products can readily be converted to the related heterocycles such as 2-isoxazoline and isoxazole. A radical-polar crossover pathway initiated by single-electron transfer from nitronate to a copper salt is proposed. ",

author = "Masayuki Iwasaki and Yuichi Ikemoto and Yasushi Nishihara",

note = "Funding Information: This work was partly supported by Grant-in-Aid for Scientific Research (KAKENHI) (No. 16K17901) from JSPS. The authors gratefully thank Megumi Kosaka and Motonari Kobayashi (Department of Instrumental Analysis, Advanced Science Research Center, Okayama University) for performing elemental analyses, and the SC-NMR Laboratory (Okayama University) for the NMR spectral measurements. Publisher Copyright: {\textcopyright} 2020 American Chemical Society.",

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doi = "10.1021/acs.orglett.0c02781",

language = "English",

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journal = "Organic Letters",

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T1 - Synthesis of 2-Isoxazoline N-Oxides by Copper-Mediated Radical Annulation of Alkenes with α-Nitrobenzyl Bromides

AU - Iwasaki, Masayuki

AU - Ikemoto, Yuichi

AU - Nishihara, Yasushi

N1 - Funding Information: This work was partly supported by Grant-in-Aid for Scientific Research (KAKENHI) (No. 16K17901) from JSPS. The authors gratefully thank Megumi Kosaka and Motonari Kobayashi (Department of Instrumental Analysis, Advanced Science Research Center, Okayama University) for performing elemental analyses, and the SC-NMR Laboratory (Okayama University) for the NMR spectral measurements. Publisher Copyright: © 2020 American Chemical Society.

PY - 2020/10/2

Y1 - 2020/10/2

N2 - Copper-mediated [3 + 2] annulation of alkenes with α-nitrobenzyl bromides has been developed. The reaction is promoted simply by a copper salt to produce the corresponding 2-isoxazoline N-oxides with perfect regioselectivity. The present method can be conducted under mild conditions, affording a diverse array of 2-isoxazoline N-oxides. The obtained products can readily be converted to the related heterocycles such as 2-isoxazoline and isoxazole. A radical-polar crossover pathway initiated by single-electron transfer from nitronate to a copper salt is proposed.

AB - Copper-mediated [3 + 2] annulation of alkenes with α-nitrobenzyl bromides has been developed. The reaction is promoted simply by a copper salt to produce the corresponding 2-isoxazoline N-oxides with perfect regioselectivity. The present method can be conducted under mild conditions, affording a diverse array of 2-isoxazoline N-oxides. The obtained products can readily be converted to the related heterocycles such as 2-isoxazoline and isoxazole. A radical-polar crossover pathway initiated by single-electron transfer from nitronate to a copper salt is proposed.

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Synthesis of 2-Isoxazoline N-Oxides by Copper-Mediated Radical Annulation of Alkenes with α-Nitrobenzyl Bromides

Abstract

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