已经通过钴 (II) 基金属基催化对 N-双同炔氨磺酰基叠氮化物证明了炔丙 C(sp 3 ) H 键的高度化学选择性分子内胺化。在 D 2h对称酰胺卟啉配体 3,5-Di t Bu-IbuPhyrin 的支持下,钴 (II) 催化的 C H 胺化在中性和非氧化条件下有效进行,无需任何添加剂,并生成 N 2作为唯一的副产品。金属自由基胺化适用于二级和三级炔丙C H 底物具有异常高的官能团耐受性,从而为功能化炔丙胺衍生物的高产合成提供了一种直接方法。
noncovalent attractive interactions through fine-tuning of the remote substituents of the D2-symmetric chiral amidoporphyrin ligand. This noncovalent interaction strategy presents a solution that may be generally applicable in controlling reactivity and enantioselectivity in intermolecularradical reactions. The Co(II)-catalyzed intermolecular C-H amination, which operates under mild conditions with the C-H
Enantioselective Cyclopropenation of Alkynes with Acceptor/Acceptor-Substituted Diazo Reagents via Co(II)-Based Metalloradical Catalysis
作者:Xin Cui、Xue Xu、Hongjian Lu、Shifa Zhu、Lukasz Wojtas、X. Peter Zhang*
DOI:10.1021/ja111334j
日期:2011.3.16
The cobalt(II) complex of a new D(2)-symmetric chiral porphyrin 3,5-diMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents, such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range
The cobalt(II) complex of new D2-symmetric chiral porphyrin 3,5-DiMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range of terminal aromatic and related conjugated alkynes with varied steric and electronic properties, providing the corresponding tri-substituted cyclopropenes in high yields with excellent enantiocontrol of the all-carbon quaternary stereogenic centers. In addition to mild reaction conditions, the Co(II)-based metalloradical catalysis for cyclopropenation features a high degree of functional group tolerance.
Application of [Co(Corrole)]
<sup>–</sup>
Complexes in Ring‐Closing C–H Amination of Aliphatic Azides via Nitrene Radical Intermediates
作者:Monalisa Goswami、Paul Geuijen、Joost. N. H. Reek、Bas de Bruin
DOI:10.1002/ejic.201701343
日期:2018.2.7
DFT calculations, the reaction is proposed to proceed via discrete open‐shell nitrene radical intermediates bearing most of their spin density at the nitrene nitrogen atom. The [CoII(Cor)]– complexes are substantially faster catalysts than the corresponding neutral [CoII(porphyrin)] complexes when applied in the same ring‐closing C–Hamination reaction under identical reaction conditions. Increasing
Controlling Enantioselectivity and Diastereoselectivity in Radical Cascade Cyclization for Construction of Bicyclic Structures
作者:Congzhe Zhang、Duo-Sheng Wang、Wan-Chen Cindy Lee、Alexander M. McKillop、X. Peter Zhang
DOI:10.1021/jacs.1c04719
日期:2021.7.28
controlling enantioselectivity as well as diastereoselectivity in radical cascade cyclization, we herein report the development of a Co(II)-based catalytic system for asymmetric radical bicyclization of 1,6-enynes with diazo compounds. Through the fine-tuning of D2-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under
自由基级联环化反应是有机合成中构建多环分子的极具吸引力的合成工具。虽然它已成功应用于天然产物和其他复杂化合物的非对映选择性合成,但自由基级联环化面临着控制对映选择性的重大挑战。作为金属自由基催化(MRC)在自由基级联环化中控制对映选择性和非对映选择性的首次应用,我们在此报告了一种基于Co(II)的催化系统的开发,用于1,6-烯炔与重氮化合物的不对称自由基双环化。通过对D 2 -对称手性酰胺卟啉作为支持配体的微调,Co(II)催化的自由基级联过程在温和条件下单次操作进行,能够不对称构建带有三个连续的多取代环丙烷稠合四氢呋喃。立体异构中心,包括两个全碳四元中心,产量高且具有优异的立体选择性。结合计算和实验研究揭示了这种新的基于 Co(II) 的级联双环化的潜在逐步自由基机制,该机制涉及几种 Co-支持的 C 中心自由基中间体的中继,包括 α-、β-、γ-、和ε-金属烷基自由基。所得到的对映体富