Synthesis of Polycyclic Spirocarbocycles via Acid-Promoted Ring-Contraction/Dearomative Ring-Closure Cascade of Oxapropellanes
Synthesis of Polycyclic Spirocarbocycles via Acid-Promoted Ring-Contraction/Dearomative Ring-Closure Cascade of Oxapropellanes
复制标题
DOI：
10.1021/acs.orglett.9b02835
复制
发表时间：
2019-09-20
期刊：
影响因子：
5.2
通讯作者：
Takasu, Kiyosei
中科院分区：
文献类型：
--
作者：
Ogawa, Naoki;Yamaoka, Yousuke;Takasu, Kiyosei
本文报道了氧杂[4.3.2]螺桨烷酸促进重排反应的发展，得到多芳稠合螺[4.5]碳环。DFT计算表明，该反应途径涉及生成的环丁基阳离子，环收缩的环丙基carbinyl阳离子，和脱芳环封闭的内部2-萘酚部分。所得到的螺碳环具有合成价值，因为它们可以通过骨架重排转化为两种不同的多环芳烃。还描述了通过中心-轴-中心手性转移合成光学纯的螺碳环。
We report herein the development of an acid-promoted rearrangement of oxa[4.3.2]propellanes to afford polyaromatic-fused spiro[4.5]carbocycles. DFT calculations suggest that the reaction pathway involves generation of a cyclobutyl cation, ring contraction to the cyclopropylcarbinyl cation, and dearomative ring closure by an internal 2-naphthol moiety. The resulting spirocarbocycles are synthetically valuable, as they could be transformed into two different polycyclic aromatic hydrocarbons via skeletal rearrangement. Syntheses of optically pure spirocarbocycles via a central-to-axial-to-central chirality transfer are also described.