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首页> 外文期刊>The Journal of Organic Chemistry >Intermolecular C-H amination of complex molecules: Insights into the factors governing the selectivity
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Intermolecular C-H amination of complex molecules: Insights into the factors governing the selectivity

机译：分子间C-H分子间胺化：洞察决定选择性的因素

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摘要

Transition-metal-catalyzed C-H amination via nitrene insertion allows the direct transformation of a C-H into a C-N bond. Given the ubiquity of C-H bonds in organic compounds, such a process raises the problem of regio- and chemoselectivity, a challenging goal even more difficult to tackle as the complexity of the substrate increases. Whereas excellent regiocontrol can be achieved by the use of an appropriate tether securing intramolecular addition of the nitrene, the intermolecular C-H amination remains much less predictable. This study aims at addressing this issue by capitalizing on an efficient stereoselective nitrene transfer involving the combination of a chiral aminating agent 1 with a chiral rhodium catalyst 2. Allylic C-H amination of terpenes and enol ethers occurs with excellent yields as well as with high regio-, chemo-, and diastereoselectivity as a result of the combination of steric and electronic factors. Conjugation of allylic C-H bonds with the π-bond would explain the chemoselectivity observed for cyclic substrates. Alkanes used in stoichiometric amounts are also efficiently functionalized with a net preference for tertiary equatorial C-H bonds. The selectivity, in this case, can be rationalized by steric and hyperconjugative effects. This study, therefore, provides useful information to better predict the site of C-H amination of complex molecules.
机译：过渡金属催化的C-H胺化（通过腈插入）可将C-H直接转化为C-N键。考虑到有机化合物中C-H键的普遍存在，这种方法提出了区域选择性和化学选择性的问题，随着底物复杂性的提高，这一挑战性目标甚至更加难以解决。尽管可以通过使用适当的系链来确保在分子内添加氮烯来实现出色的区域控制，但分子间C-H胺化仍然难以预测。这项研究旨在通过利用有效的立体选择性腈转移技术来解决这一问题，该方法涉及将手性胺化剂1与手性铑催化剂2结合使用。萜烯和烯醇醚的烯丙基CH胺化反应具有极高的收率和高的区域选择性。 ，电子和非对映选择性是空间和电子因素共同作用的结果。烯丙基C-H键与π键的结合将解释对环状底物观察到的化学选择性。以化学计量的量使用的烷烃还可以有效地官能化，并且对三级赤道C-H键有净偏好。在这种情况下，选择性可以通过空间和超共轭作用来合理化。因此，这项研究提供了有用的信息，可以更好地预测复杂分子的C-H胺化位点。

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