Synthesis of Polyynes Using Dicobalt Masking Groups
Synthesis of Polyynes Using Dicobalt Masking Groups
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DOI：
10.1021/acs.joc.7b03015
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发表时间：
2018-02-16
影响因子：
3.6
通讯作者：
Anderson, Harry L.
中科院分区：
文献类型：
--
作者：
Kohn, Daniel R.;Gawel, Przemyslaw;Anderson, Harry L.
以相应的四钴配合物为原料，通过去除配合物四碳基二苯基磷甲烷(CO -2（CO)(4)dppm）部分，制备了扩展的三异丙基硅基端盖多炔。在室温下，用单质碘在温和条件下实现了这种“掩膜炔当量”的揭开，从而有可能获得具有多达20个连续sp杂化碳原子的脆弱多炔。核磁共振、红外光谱、密度泛函理论计算和x射线晶体学表明，CO -2(CO)(4)dppm部分对聚炔具有很强的几何和空间效应，但对末端炔没有明显的电子效应。在铜催化的Eglinton偶联过程中，注意到二钴基团的不寻常的“炔跳”迁移是一个次要的副反应。
Extended triisopropylsilyl end-capped polyynes have been prepared from the corresponding tetracobalt complexes by removing the complexed dicobalt tetracarbo nyldiphenylphosphinomethane (Co-2(CO)(4)dppm) moieties. Unmasking of this "masked alkyne equivalent" was achieved under mild conditions with elemental iodine at room temperature, making it possible to obtain fragile polyynes with up to 20 contiguous sp-hybridized carbon atoms. The Co-2(CO)(4)dppm moiety has a strong geometric and steric effect on the polyyne but does not have a marked electronic effect on the terminal alkyne, as indicated by NMR and IR spectroscopy, density functional theory calculations, and X-ray crystallography. An unusual "alkyne hopping" migration of the dicobalt group was noticed as a minor side reaction during copper-catalyzed Eglinton coupling.