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Synfacts 2010(2): 0156-0156
DOI: 10.1055/s-0029-1219123
DOI: 10.1055/s-0029-1219123
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Iron-Catalyzed Synthesis of Polysubstituted Benzofurans
X. Guo, R. Yu, H. Li, Z. Li*
Renmin University of China, Beijing, P. R. of China
Further Information
Publication History
Publication Date:
21 January 2010 (online)
![](https://www.thieme-connect.de/media/synfacts/201002/lookinside/thumbnails/10.1055-s-0029-1219123-1.jpg)
Significance
The iron-catalyzed oxidative Pechmann condensation of phenols 1 with β-keto esters 2 to give polysubstituted benzofurans 3 is reported. Extensive optimization showed that the presence of a proton source such as water is crucial to obtain high yields of the desired products. Electron-rich phenols bearing ortho or para substituents were well tolerated in the reaction. In contrast, no product was obtained from phenols bearing strong EWGs (R¹ = NO2, Ac). A tentative mechanism involving first oxidative coupling to give 4 followed by condensation is proposed based on the independent synthesis of the possible intermediates.