Gold-catalyzed ketene dual functionalization and mechanistic insights:divergent synthesis of indenes and benzo[d]oxepines

• 作者: Ming Bao Jinzhou Chen Chao Pei Sujie Zhang Jinping Lei Wenhao Hu Xinfang Xu
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2021,（5）
• 所属期刊栏目: ARTICLES
• 页码范围: 778-787
• 页数: 10页
• 语种: 英文

摘要

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 cy-cloaddition 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.