• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Chiral Organoborane Lewis Pairs Derived from Pyridylferrocene
【24h】

Chiral Organoborane Lewis Pairs Derived from Pyridylferrocene

机译：吡啶基二茂铁的手性有机硼烷路易斯对

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In an effort to develop a new class of redox-active chiral Lewis pairs, pyridine and borane moieties with different steric and electronic properties were introduced onto a planar chiral 1,2-disubstituted ferrocene framework. Metathesis of lithiated, stannylated, or mercuriated pyridylferrocenes with boron halides afforded (pR)-2-[bis(pentafluorophenyl) boryl]-1-(3,5-dimethylpyrid-2-yl)ferrocene (4-Pf), (pR)-2-[dimesitylboryl]-1-(3,5-dimethylpyrid-2-yl)ferrocene (4-Mes), (pS)-2-(bis(pentafluorophenyl)boryl)-1-(2-trimethylsilylpyrid-6-yl)ferrocene (5-Pf), or (pS)-2-[dimesitylboryl]-1-(2-trimethylsilylpyrid-6-yl)ferrocene (5-Mes). The borylated products were analyzed by multinuclear NMR spectroscopy, HRMS, and single-crystal X-ray diffraction. Chiral HPLC and optical-rotation measurements were employed to assess the stereoselectivity of the borylation process and to establish the correct stereochemical assignments. The strength of the B-N interactions were investigated in solution and in the solid state. Compounds 4-Pf and 4-Mes formed robust 'closed' B-N heterocyclic systems that proved to be perfectly stable to air and moisture, whereas 5-Pf established a dynamic equilibrium, in which the B-N heterocycle was observed exclusively at room temperature, but opened up at high temperature according to ~(19)F NMR exchange spectroscopy data. As a consequence, 5-Pf reacted readily with a molecule of water to generate a ring-opened pyridinium borate. The combination of bulky borane and bulky pyridyl groups in 5-Mes led to a completely 'open' frustrated Lewis pair system with uncomplexed pyridine and borane groups, even at room temperature. Electrochemical studies were performed and the effect of preparative ferrocene oxidation on the structural features was also explored.
机译：为了开发新型的氧化还原活性手性路易斯对，将具有不同空间和电子性质的吡啶和硼烷部分引入平面手性1,2-二取代的二茂铁骨架上。将锂化，锡烷基化或汞化吡啶基二茂铁与卤化硼复分解得到（pR）-2- [双（五氟苯基）硼基] -1-（3,5-二甲基吡啶-2-基）二茂铁（4-Pf），（pR） -2- [dimesitylboryl] -1-（3,5-二甲基吡啶-2-基）二茂铁（4-Mes），（pS）-2-（双（五氟苯基）硼基）-1-（2-三甲基甲硅烷基吡啶-6-基）二茂铁（5-Pf）或（pS）-2- [dimesitylboryl] -1-（2-三甲基甲硅烷基吡啶-6-基）二茂铁（5-Mes）。通过多核NMR光谱，HRMS和单晶X射线衍射分析硼化产物。手性HPLC和旋光度测量用于评估硼酸酯化过程的立体选择性并建立正确的立体化学分配。在溶液和固态下研究了B-N相互作用的强度。化合物4-Pf和4-Mes形成了坚固的“封闭” BN杂环系统，该系统被证明对空气和水分完全稳定，而5-Pf建立了动态​​平衡，其中BN杂环仅在室温下观察到，但开放根据〜（19）F NMR交换光谱数据，在高温下结果，5-Pf容易与水分子反应以生成开环的硼酸吡啶鎓。 5-Mes中笨重的硼烷和吡啶基的结合导致完全“开放”的受阻的Lewis对体系，即使在室温下也没有复杂的吡啶和硼烷基团。进行了电化学研究，还研究了制备二茂铁氧化对结构特征的影响。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号