Control over Organometallic Intermediate Enables Cp*Co(III) Catalyzed Switchable Cyclization to Quinolines and Indoles

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• 作者：Qingquan Lu ; Suhelen Vásquez-Céspedes ; Tobias Gensch ; Frank Glorius
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：April 1, 2016
• 年：2016
• 卷：6
• 期：4
• 页码：2352-2356
• 全文大小：419K
• ISSN：2155-5435

文摘

Achieving controllable C–H functionalization to elaborate valuable compounds from simple chemicals is attractive and highly desirable, especially if nonprecious transition metal catalysts can be used. However, controlling selectivity in these transformations remains a continuous challenge to synthetic chemists. Herein, we show for the first time that control over the reactive organometallic intermediate enables the switchable synthesis of quinoline and indole from amides and alkynes through C–H activation using Cp*Co(III). The keys to this strategy are (1) introducing a Lewis acid to greatly accelerate the dehydrative cyclization, which can outcompete dehydrogenative cyclization, and (2) tuning the directing group to facilitate the dehydrogenative cyclization and inhibit dehydrative cyclization.