作者:Zili Chen、Yu-Xin Zhang、Yan An、Xin-Li Song、Ya-Hui Wang、Li-Li Zhu、Lin Guo
DOI:10.1002/ejoc.200900858
日期:2009.10
reversed E/Z selectivity is obtained with Et3B/O2. Two competitive pathways are suggested for the formation of vinyl radical B: zinc-radical exchange (route a) followed by protonation provides E-configuration products exclusively through Zn(II) complexation. Hydrogen abstraction by vinyl radicals (route b) yields mainly Z isomers.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
通过使用 Me2Zn/O2 作为自由基引发剂,研究了醚与末端炔烃的直接自由基加成,以提供具有高 E-选择性的 2-乙烯基醚衍生物,而使用 Et3B/O2 获得反向 E/Z 选择性。建议形成乙烯基自由基 B 的两种竞争途径:锌自由基交换(途径 a),然后质子化仅通过 Zn(II) 络合提供 E 构型产物。乙烯基自由基夺氢(路线 b)主要产生 Z 异构体。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)