Photochemical generation and characterization of the 5-endo-10,11-dihydrodibenzoazepine nitrenium ion
Photochemical generation and characterization of the 5-endo-10,11-dihydrodibenzoazepine nitrenium ion
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DOI：
10.1007/s43630-022-00267-3
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发表时间：
2022-07-22
影响因子：
3.1
通讯作者：
Falvey，Daniel E.
中科院分区：
文献类型：
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作者：
Chinn，Edward S.;Falvey，Daniel E.
合成了5-内酯-10,11-二氢氮卓氮离子(1)的光化学前体，并通过激光闪光光解和稳定产物分析对中间体进行了表征。此外，对氮离子进行了离散傅立叶变换计算。为了确定2碳桥对1碳桥的反应和性质的影响，我们将这些结果与早期二苯基氮离子的研究结果进行了比较。结果表明，桥接基团提供的几何约束(a)使1相对于单线态的三重态不稳定；(b)通过抑制后者可能的单分子环化途径，大大增加了1相对toPh2N+的寿命；(c)适度增加了亲核加成到环碳上的屏障。图形抽象
A photochemical precursor to the 5-endo-10,11-dihydroazepine nitrenium ion (1)was synthesized and used to characterize the intermediate by laser flash photolysis and stable product analysis. In addition, DFT calculations were carried out on the nitrenium ion. These results were compared with earlier studies on the diphenylnitrenium ion in order to ascertain the effect of the 2 carbon bridge on the reactions and properties of1.It is shown that the geometric constraints provided by the bridging group (a) destabilize the triplet state of1relative to the singlet state (b) substantially increase the lifetime of1relative toPh2N+by inhibiting the unimolecular cyclization pathway possible in the latter and (c) modestly increases the barrier for nucleophilic addition to the ring carbons.Graphical abstract