Computational Mechanism Study on Allylic Oxidation of cis-Internal Alkenes: Insight into the Lewis Acid-Assisted Bronsted Acid (LBA) Catalysis in Heteroene Reactions
Computational Mechanism Study on Allylic Oxidation of cis-Internal Alkenes: Insight into the Lewis Acid-Assisted Bronsted Acid (LBA) Catalysis in Heteroene Reactions
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顺式内烯烃烯丙基氧化的计算机理研究：深入了解杂烯反应中路易斯酸辅助的布朗斯台德酸 (LBA) 催化
DOI：
10.1021/acs.joc.8b02130
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发表时间：
2018
影响因子：
3.6
通讯作者：
Xue Ying
中科院分区：
文献类型：
--
作者：
Yang Yongsheng;Yang Xin;Zhang Yan;Xue Ying
烯烃的烯丙基C-H催化氧化反应在药物化学领域具有重要的应用价值。最近，坦巴尔等人提出了自己的观点。在Lewis酸辅助的手性Brnsted酸(LBA)的辅助下，通过杂烯反应促进了这一转化，并实现了失活的顺式内部烯烃的选择性烯丙基氧化生成多种氧化产物。通过密度泛函理论(DFT)计算，我们对杂烯反应的机理进行了详细的研究，并成功地定位了一个新的催化过程，该过程能够很好地解释实验观察。为LBA催化的杂烯反应设计了四种不同的反应路径(路径A、B、C和D)。我们发现路径D具有最低的总自由能势垒，该路径经历了一个质子化过程来活化亲烯苯磺酰硫亚胺。途径E的提出是为了得到一个次要的对映体。由它们的能量差计算出的理论对映体比与实验结果一致。对于杂烯反应，我们提出了一个新的反应机理，可以辅助相关的转化和新型LBA催化剂的设计。
The catalytic allylic C–H oxidation of alkenes plays an important role in the field of medicine chemistry. Recently, Tambar et al. improved this transformation via a heteroene reaction with the assistance of a Lewis acid-assisted chiral Brønsted acid (LBA) and achieved a selective allylic oxidation of inactivatedcis-internal alkenes to versatile oxidation products. By means of density functional theory (DFT) calculations, we provided a detailed investigation on the mechanism of the heteroene reaction and successfully located a new catalytic process, which is able to explain the experimental observations very well. Four different reactive pathways (pathways A, B, C, and D) for the LBA-catalyzed heteroene reaction have been designed. We found pathway D, which undergoes a protonation process for the activation of enophile benzenesulfonyl sulfurimide, has the lowest overall free energy barrier. Pathway E was put forward to lead to a minor enantiomer. The theoretical enantiomeric ratio calculated via their energy difference is consistent with the experimental report. For the heteroene reaction, we proposed a new reaction mechanism, which can assist in related transformations and the design of new LBA catalysts.