Synthetic and Mechanistic Investigation of an Oxime Ether Electrocyclization Approach to Heteroaromatic Boronic Acid Derivatives
作者:Helena Mora-Radó、Lia Sotorríos、Matthew P. Ball-Jones、Laurent Bialy、Werngard Czechtizky、María Méndez、Enrique Gómez-Bengoa、Joseph P. A. Harrity
DOI:10.1002/chem.201802350
日期:2018.7.5
observation that there is a direct relationship between oxime ether stereochemistry and reactivity towards electrocyclization. Specifically, E‐oxime ethers are found to be significantly more reactive than their Z‐counterparts (stereochemistry relative to azatriene scaffold). In contrast, the configuration at the azatriene alkene terminus has little impact on reaction rates. Computational analysis offers a rationale
通过diboration /6π-电环化序列可以很容易地获得一系列功能化的杂芳族硼酸衍生物。这项研究揭示了令人惊讶的发现,即肟醚的立体化学和对电环化的反应性之间存在直接的关系。具体而言,ê -肟醚被发现是显著比它们的反应性更强ž -counterparts(相对于azatriene支架的立体化学)。相反,在氮杂三烯烯烃末端的构型对反应速率几乎没有影响。计算分析为这种观察提供了理论依据;N个孤对→C = Cπ*轨道相互作用降低E的电环化中的过渡态能量-肟醚。最后,可以通过光解促进的E → Z异构化和电环化序列将未反应的Z-肟醚转化为相应的杂环产物。