Gold-catalyzed ketene dual functionalization and mechanistic insights: divergent synthesis of indenes and benzo[d]oxepines
Gold-catalyzed ketene dual functionalization and mechanistic insights: divergent synthesis of indenes and benzo[d]oxepines
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DOI：
10.1007/s11426-020-9954-6
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发表时间：
2021-03-17
影响因子：
9.6
通讯作者：
Xu, Xinfang
中科院分区：
文献类型：
--
作者：
Bao, Ming;Chen, Jinzhou;Xu, Xinfang
提出了一种前所未有的金催化烯酮C=O/C=C双官能化方法。机理研究和密度泛函理论（DFT）计算表明，该反应首先由金催化的重氮酮Wolff重排生成烯酮中间体，然后是分子间亲核加成，最后通过烯醇中间体进行两次不同的环化过程。在醇作为亲核试剂的情况下，反应通过c -5内切碳环化生成独立产物；而当吲哚/吡咯作为亲核试剂递送7元苯并[d]氧平时，o- 7-内切环化主要发生。与已有文献记载的环加成和亲核加成反应相比，该级联反应具有一种新的反应模式，即通过亲核和亲电试剂依次加成使烯酮双官能化。
An unprecedented gold-catalyzed ketene C=O/C=C bifunctionalization method has been developed. Mechanistic studies and density function theory (DFT) calculations indicate that the reaction is initiated by gold-catalyzed Wolff rearrangement of diazoketone to form the ketene intermediate, followed by intermolecular nucleophilic addition and terminated with two divergent cyclization processes via enol intermediates. In the case with alcohols as the nucleophiles, the reaction goes through a C-5-endo-dig carbocyclization to give the indene products; whereas, O-7-endo-dig cyclization occurs dominantly when indoles/pyrroles are used as the nucleophiles, delivering the 7-membered benzo[d]oxepines. In comparison with the well-documented cycloaddition and nucleophilic addition reactions, this cascade reaction features a novel reaction pattern for the ketene dual functionalization through addition with nucleophile and electrophile in sequence.