Modulation of Borylnitrene Reactivity in CH insertion and CC cycloaddition reactions by intramolecular dative Interactions

氮烯是有机合成中的活性中间体。硼基氮烯是硼衍生物，其在其电子单重态下是特别强的亲电物质。它们与CH键无选择性地反应，甚至可以活化非常惰性的甲烷分子。在本研究项目中，将研究具有可变环尺寸（五至八元环）和可变杂元素（E = NR，O，S）的杂环硼基氮烯。构象柔性随环大小和E的给体强度的变化通过分子内E -> N配位相互作用强度的扩展来调节硼基氮烯的电子结构和反应活性。作为氮烯反应的典型代表，CH插入和[2+1]环加成反应中环尺寸和给体元素对硼氮烯结构-反应性关系的影响是本研究项目的重点。采用基质分离和经典溶液相产物分析方法，测定硼氮烯化学的化学选择性、区域选择性、非对映选择性和对映选择性。预计该研究项目将为borylnitrenes的反应性提供基本的见解，并最终有可能采用分子内配位相互作用来调节反应性。

Nitrenes are reactive intermediates in organic synthesis. Borylnitrenes are boron derivatives that are particularly strong electrophilic species in their electronic singlet state. They react unselectively with CH bonds and can even activate the quite inert methane molecule. In this research project heterocyclic borylnitrenes of variable ring size (five to eight membered rings) and with variable hetero element (E = NR, O, S) are to be investigated. The variation of the conformational flexibility with ring size and the donor strength of E modulates the electronic structure and the reactivity of the borylnitrenes through the extend of the strength of the intramolecular E -> N dative interaction. The analysis of the structure – reactivity relationship of the borylnitrenes depending on ring size and donor element in CH insertions and [2+1] cycloadditions as typical representative nitrene reactions is the focus of this research project. Using the method of matrix isolation and classical solution phase product analyses the chemo-, regio-, diastereo- and enantioselectivity of borylnitrene chemistry are to be determined. It is expected that the research project provides fundamental insight into the reactivity of borylnitrenes and that it will be ultimately possible to tune reactivity employing intramolecular dative interactions.