Visible‐Light‐Induced
<i>ortho</i>
‐Selective Migration on Pyridyl Ring: Trifluoromethylative Pyridylation of Unactivated Alkenes
作者:Jinwon Jeon、Yu‐Tao He、Sanghoon Shin、Sungwoo Hong
DOI:10.1002/anie.201912746
日期:2020.1.2
alkenes. The overall process is initiated by the selective addition of a CF3 radical to the alkene to provide a nucleophilicalkyl radical intermediate, which enables an intramolecular endo addition exclusively to the ortho-position of the pyridinium salt. Both secondary and tertiary alkyl radicals are well-suited for addition to the C2-position of pyridinium salts to ultimately provide synthetically
A novel strategy involving visible-light-induced functionalization of alkenes for the synthesis of substituted aziridines was developed. The readily prepared N-protected 1-aminopyridinium salts were used for the generation of N-centered radicals. This approach allowed the synthesis of aziridines bearing various functional groups with excellent diastereoselectivity under mild conditions. Moreover, this
Visible-Light-Enabled <i>Ortho</i>-Selective Aminopyridylation of Alkenes with <i>N</i>-Aminopyridinium Ylides
作者:Yonghoon Moon、Wooseok Lee、Sungwoo Hong
DOI:10.1021/jacs.0c05025
日期:2020.7.15
By utilizing an underexplored reactivity mode of N-aminopyridinium ylides, we developed the visible-light-induced ortho-selective aminopyridylation of alkenes via radical-mediated 1,3-dipolar cycloaddition. The photocatalyzed single-electron oxidation of N-aminopyridinium ylides generates the corresponding radical cations that enable previously inaccessible 1,3-cycloaddition with a broader range of
通过利用 N-氨基吡啶鎓叶立德的未充分探索的反应模式,我们通过自由基介导的 1,3-偶极环加成开发了可见光诱导的烯烃邻位选择性氨基吡啶化。N-氨基吡啶鎓叶立德的光催化单电子氧化产生相应的自由基阳离子,使以前无法实现的1,3-环加成与更广泛的烯烃底物成为可能。所得的环加成加合物迅速进行随后的 NN 键均裂,赋予显着的热力学驱动力以产生各种 β-氨基乙基吡啶。值得注意的是,在无金属和温和条件下,氨基和吡啶基可以通过模块化控制邻位选择性和 1,2- 顺式非对映选择性安装到活化和未活化的烯烃中。
Micellar Catalysis: Visible‐Light Mediated Imidazo[1,2‐
<i>a</i>
]pyridine C—H Amination with
<i>N</i>
‐Aminopyridinium Salt Accelerated by Surfactant in Water
A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported, charactering mild and environmentally benign conditions, as well as great functional group tolerance. Micelles with negatively charged polar surface and hydrophobic core formed from sodium dodecyl sulfate serve as an ideal medium for visible-light
报道了在水中表面活性剂的辅助下咪唑并[1,2- a ]吡啶与N-氨基吡啶鎓盐胺化的光促进无金属方案,具有温和和环境友好的条件,以及良好的官能团耐受性. 具有带负电荷的极性表面和由十二烷基硫酸钠形成的疏水核的胶束是可见光介导的阳离子吡啶盐和咪唑并[1,2- a ]吡啶在水相中发生自由基反应的理想介质。带正电荷的N-氨基吡啶鎓与带负电荷的胶束表面之间的静电相互作用在该方法中具有重要意义。
Direct Vicinal Disubstitution of Diaryliodonium Salts by Pyridine<i>N</i>-oxides and<i>N</i>-amidates by a 1,3-Radical Rearrangement
Paired off: The title reaction leads to a series of o‐pyridinium phenols (1) and anilines (2). The experimental and computational studies indicate that the key step involves homolytic cleavage to give a radical pair, which undergoes solvent‐cage recombination to give the product.