Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes
| العنوان: | Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes |
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| المؤلفون: | Jing Ke, Wan-Chen Cindy Lee, Xiaoxu Wang, Yong Wang, Xin Wen, X. Peter Zhang |
| المصدر: | J Am Chem Soc |
| بيانات النشر: | American Chemical Society (ACS), 2022. |
| سنة النشر: | 2022 |
| مصطلحات موضوعية: | Colloid and Surface Chemistry, Molecular Structure, Cyclization, Cobalt, Diazonium Compounds, General Chemistry, Alkenes, Biochemistry, Article, Catalysis |
| الوصف: | α-Alkynyldiazomethanes, generated in situ from the corresponding sulfonyl hydrazones in the presence of a base, can serve as effective metalloradicophiles in Co(II)-based metalloradical catalysis (MRC) for asymmetric cyclopropanation of alkenes. With D(2)-symmetric chiral amidoporphyrin 2,6-DiMeO-QingPhyrin as the optimal supporting ligand, the Co(II)-based metalloradical system can efficiently activate different α-alkynyldiazomethanes at room temperature for highly asymmetric cyclopropanation of a broad range of alkenes. This catalytic radical process provides a general synthetic tool for stereoselective construction of alkynyl cyclopropanes in high yields with high both diastereoselectivity and enantioselectivity. Combined computational and experimental studies offer several lines of evidence in support of the underlying stepwise radical mechanism for the Co(II)-catalyzed olefin cyclopropanation involving a unique α-metalloradical intermediate that is associated with two resonance forms of α-Co(III)-propargyl radical and γ-Co(III)-allenyl radical. The resulting enantioenriched alkynyl cyclopropanes, as showcased with several stereospecific transformations, may serve as valuable chiral building blocks for stereoselective organic synthesis. |
| تدمد: | 1520-5126 0002-7863 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::457dbc7c81f6f1c3da7ddc90cac67cb0Test https://doi.org/10.1021/jacs.1c13154Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....457dbc7c81f6f1c3da7ddc90cac67cb0 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15205126 00027863 |
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