Unlocking the 5‐
<i>exo</i>
Pathway with the Au
<sup>I</sup>
‐Catalyzed Alkoxycyclization of 1,3‐Dien‐5‐ynes
作者:Cintia Virumbrales、Samuel Suárez‐Pantiga、Marta Marín‐Luna、Carlos Silva López、Roberto Sanz
DOI:10.1002/chem.202001296
日期:2020.7.8
1‐monosubstituted (E )‐1,3‐dien‐5‐ynes. On the contrary, the corresponding Z isomers evolve affording formal 6‐endo cyclization products. In addition, mechanistic exploration supports a highly stabilized carbocation as a key intermediate instead of a highly constrained cyclopropyl gold carbene from E isomers, and also accounts for the well differentiated reactivity observed between both E /Z geometrical isomers
描述了第一个普通的区域和立体选择性5 exo金(I)催化的特定1,5-烯类(例如1,3-dien-5炔)的烷氧基环化反应,尽管已知1,5烯几乎不约而同地进行通过内切下金催化的环化反应。起始的1,3-二烯-5-炔基中末端烯烃的构型在反应的区域化学结果中起关键作用。从1-单取代(E)-1,3-dien-5-ynes合成了许多有趣的烷氧基官能化亚烷基环戊烯。相反,相应的Z异构体不断演化,形成了正式的6-内环化产品。此外,机理探索支持高度稳定的碳正离子作为关键中间体,而不是来自E异构体的高度约束的环丙基金卡宾,并且还解释了在E / Z几何异构体之间观察到的差异明显的反应性以及反应。