Synthesis of Carbazoles and Carbazole-Containing Heterocycles via Rhodium-Catalyzed Tandem Carbonylative Benzannulations

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• 作者：Wangze Song ; Xiaoxun Li ; Ka Yang ; Xian-liang Zhao ; Daniel A. Glazier ; Bao-min Xi ; Weiping Tang
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：April 1, 2016
• 年：2016
• 卷：81
• 期：7
• 页码：2930-2942
• 全文大小：866K
• ISSN：1520-6904

文摘

Polycyclic aromatic compounds are important constituents of pharmaceuticals and other materials. We have developed a series of Rh-catalyzed tandem carbonylative benzannulations for the synthesis of tri-, tetra-, and pentacyclic heterocycles from different types of aryl propargylic alcohols. These tandem reactions provide efficient access to highly substituted carbazoles, furocarbazoles, pyrrolocarbazoles, thiophenocarbazoles, and indolocarbazoles. While tricyclic heterocycles could be derived from vinyl aryl propargylic alcohols, tetra- and pentacyclic heterocycles were synthesized from diaryl propargylic alcohols. The tandem carbonylative benzannulation is initiated by a π-acidic rhodium(I) catalyst-mediated nucleophilic addition to alkyne to generate a key metal-carbene intermediate, which is then trapped by carbon monoxide to form a ketene species for 6π electrocyclization. Overall, three bonds and two rings are formed in all of these tandem carbonylative benzannulation reactions.