State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Chemistry. 2010 May 3;16(17):5163-72. doi: 10.1002/chem.200903131.
BF(3)OEt(2)-catalyzed reactions of vinylidenecyclopropanes (VDCPs) 1 with bis(aryl)methanols 2 were thoroughly investigated. When VDCPs 1 reacted with electron-rich bis(aryl)methanols 2, diastereomeric rotamers of indene derivatives formed in excellent yields by a novel cationic 1,4-aryl migration between two carbon atoms and the subsequent intramolecular Friedel-Crafts reaction pathways in the presence of BF(3).OEt(2) under mild conditions. As for electron-deficient or less-electron-rich bis(aryl)methanols 2, either trialkene products formed in good yields by direct deprotonation, or another type of indene derivative was produced by direct intramolecular Friedel-Crafts reaction, depending on the substituents on the cyclopropane of VDCPs. In addition, DFT calculations were carried out to explain the experimental results. Plausible mechanisms for all these transformations are proposed on the basis of the experimental and computational results.
BF(3)OEt(2)催化的乙烯基环丙烷(VDCPs)1 与双(芳基)甲醇 2 的反应进行了深入研究。当 VDCPs 1 与富电子双(芳基)甲醇 2 反应时，在 BF(3)的存在下，通过两个碳原子之间的新型阳离子 1,4-芳基迁移和随后的分子内傅克反应途径，以优异的收率形成了茚衍生物的非对映异构体旋转异构体。在温和条件下。对于缺电子或较少富电子的双(芳基)甲醇 2，通过直接去质子化可以得到三烯烃产物，或者通过直接分子内傅克反应可以得到另一种类型的茚衍生物，这取决于 VDCPs 中环丙烷上的取代基。此外，还进行了 DFT 计算来解释实验结果。根据实验和计算结果，提出了所有这些转化的合理机制。
