Zinc-Catalyzed Dehydrogenative Silylation of Indoles
Zinc-Catalyzed Dehydrogenative Silylation of Indoles
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DOI：
10.1021/acs.organomet.7b00382
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发表时间：
2017-08
期刊：
影响因子：
2.8
通讯作者：
Kyohei Yonekura;Y. Iketani;Masaru Sekine;Tomohiro Tani;Fumiya Matsui;Daiki Kamakura;T. Tsuchimoto
中科院分区：
文献类型：
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作者：
Kyohei Yonekura;Y. Iketani;Masaru Sekine;Tomohiro Tani;Fumiya Matsui;Daiki Kamakura;T. Tsuchimoto
一个独特的由三氟化锌和吡啶组成的Lewis酸碱体系被发现是以脱氢方式生成N(吲哚)-硅键的有效催化剂。在丁腈介质中的执行带来了锌-吡啶体系的最佳性能，这使得灵活的吲哚和氢化硅烷能够参与，从而以高到极高的产率获得各种N-硅烷吲哚。丁腈溶剂中的锌-吡啶体系在吲哚的氮原子有取代基的情况下也适用于相应的C-硅基化反应。除吲哚外，吡咯、咔唑、芳胺和噻吩类底物也经历脱氢N-和/或C-硅基化。机理研究表明，路易斯酸锌的作用是活化氢硅烷。根据动力学同位素效应实验，发现该反应的速率决定步骤涉及吲哚-氢键断裂阶段。动力学研究表明，吲哚-b反应是一种有效的反应。
A unique Lewis acid/base system consisting of zinc triflate and pyridine was found to act as an effective catalyst for making an N(indolyl)–Si bond in a dehydrogenative fashion. Execution in a nitrile medium brings out the best performance of the Zn–pyridine system, which enables participation of flexible pieces of indoles and hydrosilanes, thereby giving diverse N-silylindoles in high to excellent yields. The Zn–pyridine system in the nitrile solvent is also applicable to the corresponding C-silylation in the case that the nitrogen atom of indoles has a substituent. Pyrrole, carbazole, arylamine, and thiophene substrates other than indoles undergo the dehydrogenative N- and/or C-silylation as well. Mechanistic studies showed that the role of the zinc Lewis acid is to activate the hydrosilane. The rate-determining step of the present reaction was found to be involved in the stage of the indolyl–H bond cleavage, on the basis of kinetic isotope effect experiments. Kinetic studies indicated that the indole-b...