Characterization of Highly Coordinated Allylgermanes: Pivotal Players for Enhanced Nucleophilicity and Stereoselectivity
Characterization of Highly Coordinated Allylgermanes: Pivotal Players for Enhanced Nucleophilicity and Stereoselectivity
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高度配位的烯丙基锗烷的表征：增强亲核性和立体选择性的关键因素
DOI：
10.1002/asia.202000392
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yasuda Makoto
中科院分区：
文献类型：
--
作者：
Minami Yohei;Nishida Kento;Konishi Akihito;Yasuda Makoto
通过 X 射线晶体学对具有 4、5 和 6 配位锗中心的烯丙基锗烷进行了表征。成功分离出阳离子 6 配位 14 族烯丙基金属，迄今为止，它们被认为是烯丙基化的过渡态结构。形成高配位态显着增强了烯丙基锗烷的反应活性。与反应活性较低的 4 配位烯丙基锗烷相比，高度配位的物种很容易与几种醛发生反应。此外，高配位态对取决于外部添加剂的烯丙基化的E/Z选择性产生显着影响。配位结构对Ge中心周围的电子和空间环境产生巨大影响，从而实现醛的几何控制烯丙基化。
Allylgermanes with a 4‐, 5‐, and 6‐coordinated germanium center were characterized by X‐ray crystallography. Cationic 6‐coordinated group 14 allylmetals, which were hitherto assumed to be a transition‐state structure of allylations, were successfully isolated. Forming high coordination states significantly enhanced the reactivity of the allylgermanes. In contrast to the 4‐coordinated allylgermanes with low reactivity, the highly coordinated species readily reacted with several aldehydes. Furthermore, the high coordination states exerted a significant effect on theE/Zselectivity of allylation depending on external additives. The coordination structure had a dramatic influence on the electronic and steric environments around the Ge center, enabling the geometrically controlled allylation of aldehydes.