Elucidation of the Mechanism for the S-N-type Smiles Rearrangement on Pyridine Rings
Elucidation of the Mechanism for the S-N-type Smiles Rearrangement on Pyridine Rings
复制标题
吡啶环S-N型微笑重排机制的阐明
DOI：
10.1071/ch08205
复制
发表时间：
2009-01-01
影响因子：
1.1
通讯作者：
Wang, Lushan
中科院分区：
文献类型：
--
作者：
Li, Jinghua;Wang, Lushan
Smiles重排（SR）是合成杂环化合物的重要策略。许多含吡啶基团的配合物具有生物活性。虽然在吡啶环上的SR得到含吡啶基团的杂环化合物已经取得了成功，但对SR的详细机理却知之甚少。本文报道了一种典型的s - n型SR反应的理论研究，该反应涉及噻嗪酮融合吡啶的合成。我们研究了ipso-SR过程和邻位上的直接亲核取代反应，以使实验观察到的ipso-SR产物合理化。计算结果表明，ipso-SR由分子内ipso位置取代和随后的环闭合两个基本步骤组成，决定速率步骤的势垒为65.98 kJ mol(-1)，整个反应的放热量为116.94 kJ mol(-1)，证实了该反应在温和的实验条件下（如受控微波加热）是动力学可行和热力学有利的。本研究结果为了解吡啶环上的s - n型SR合成含吡啶基团杂环提供了清晰的图像。
The Smiles rearrangement (SR) is an important strategy for synthesizing heterocyclic compounds. Many pyridine moiety-containing complexes are biologically active. Although the success has been archived in the development of the SR on the pyridine ring to obtain pyridine moiety-containing heterocyclic compounds, not much is known about the detailed SR mechanism. Here, we report a theoretical study on a typical S-N-type SR reaction involved in the synthesis of thiazinone-fused pyridines. We studied both the ipso-SR process and the direct nucleophilic substitution reactions on the ortho-positions to rationalize the experimentally observed ipso-SR product. The calculated results show the ipso-SR consists of two elementary steps, the intramolecular ipso-position substitution and subsequent ring closure, and the barrier for the rate-determining step is 65.98 kJ mol(-1) and the overall reaction is exothermic by 116.94 kJ mol(-1), confirming the reaction is kinetically feasible and thermodynamically favourable under mild experimental conditions (such as controlled microwave heating). The present results provide a clear picture for understanding the S-N-type SR on the pyridine ring to synthesize pyridine moiety-containing heterocycles.