• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Computational Mechanistic Elucidation of the Intramolecular Aminoalkene Hydroamination Catalysed by Iminoanilide Alkaline-Earth Compounds
【24h】

Computational Mechanistic Elucidation of the Intramolecular Aminoalkene Hydroamination Catalysed by Iminoanilide Alkaline-Earth Compounds

机译：氨基苯胺碱土类化合物催化的分子内氨基烯烃加氢胺化反应的计算机理研究

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

A comprehensive computational exploration of plausible alternative mechanistic pathways for the intramolecular hydroamination (HA) of aminoalkenes by a recently reported class of kinetically stabilised iminoanilide alkaline-earth silylamido compounds [{N-N}Ae{N(SiMe3)(2)}.(thf)(n)] ({N-N}=iminoanilide; Ae=Ca, Sr, Ba) is presented. On the one hand, a proton-assisted concerted N-C/C-H bond-forming pathway to afford the cycloamine in a single step can be invoked and on the other hand, a stepwise sigma-insertive pathway that involves a fast, reversible migratory olefin 1,2-insertion step linked to a less rapid, irreversible metal-C azacycle tether sigma-bond aminolysis. Notably, these alternative mechanistic avenues are equally consistent with reported key experimental features. The present study, which employs a thoroughly benchmarked and reliable DFT methodology, supports the prevailing mechanism to be a stepwise s-insertive pathway that sees an initial conversion of the {N-N} Ae silylamido into the catalytically competent {N-N} Ae amido-alkene compound and involves thereafter facile and reversible insertive N-C bond-forming ring closure, linked to irreversible intramolecular Ae C tether sigma-bond aminolysis at the transient {N-N} Ae alkyl intermediate. Turnover-limiting protonolysis accounts for the substantial primary kinetic isotope effect observed; its DFT-derived barrier satisfactorily matches the empirically determined Eyring parameter and predicts the decrease in rate observed across the series Ca > Sr > Ba correctly. Non-competitive kinetic demands militate against the operation of the concerted proton-assisted pathway, which describes N-C bond-forming ring closure triggered by concomitant amino proton delivery at the C=C linkage evolving through a multi-centre TS structure. Valuable insights into the catalytic structure-activity relationships are unveiled by a detailed comparison of [{N-N} Ae(NHR)] catalysts. Moreover, the intriguingly opposite trends in reactivity observed in intramolecular (Ca > Sr > Ba) and intermolecular (Ca < Sr < Ba) HA catalysis for the studied family of iminoanilide alkaline-earth amido catalysts are rationalised.
机译：最近报道的一类动力学稳定的亚氨基苯胺碱土类甲硅烷基酰胺化合物[{NN} Ae {N（SiMe3）（2）}。（thf）对氨基烯烃进行分子内加氢胺化（HA）的可能替代机理的综合计算探索（n）]（{NN} ＝亚氨基苯胺; Ae ＝ Ca，Sr，Ba）。一方面，可以调用质子辅助的协调一致的NC / CH键形成途径，从而一步即可提供环胺;另一方面，可以采用逐步sigma插入途径，该途径涉及快速，可逆的迁移性烯烃1， 2插入步骤与速度较快，不可逆的金属C氮杂双环系链sigma-bond氨解相关。值得注意的是，这些替代的机制途径与报道的关键实验特征同样一致。本研究采用了全面的基准测试和可靠的DFT方法，支持目前流行的机制是逐步的s插入途径，即看到{NN} Ae硅酰胺基分子初步转化为具有催化作用的{NN} Ae酰胺基烯烃化合物。并且此后涉及到在瞬态{NN} Ae烷基中间体处与不可逆的分子内Ae C系链sigma-bond氨解反应相关的便捷且可逆的插入式NC键形成环闭合。营业额限制的质子分解占观察到的主要的初级动力学同位素效应。其DFT派生的势垒与经验确定的Eyring参数完全匹配，并正确预测了在Ca> Sr> Ba系列中观察到的速率下降。非竞争性动力学需求阻碍了协同的质子辅助途径的运行，该途径描述了N-C键形成环的闭合是由在多中心TS结构演变的C = C键处伴随的氨基质子传递触发的。通过对[{N-N} Ae（NHR）]催化剂的详细比较，揭示了对催化结构-活性关系的宝贵见解。此外，合理化的分子内（Ca> Sr> Ba）和分子间（Ca

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