Organic & Biomolecular Chemistry 2012-11-28

Metal-free catalyzed oxidative trimerization of indoles by using TEMPO in air: a biomimetic approach to 2-(1H-indol-3-yl)-2,3'-biindolin-3-ones.

Wen-Bing Qin, Qiong Chang, Yun-Hong Bao, Ning Wang, Zheng-Wang Chen, Liang-Xian Liu

Index: Org. Biomol. Chem. 10(44) , 8814-21, (2012)

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Abstract

A simple, convenient and efficient metal-free catalyzed oxidative trimeric reaction of indoles toward a variety of 2-(1H-indol-3-yl)-2,3'-biindolin-3-one derivatives in moderate to excellent yields has been developed. This transformation proceeds via a tandem oxidative homocoupling reaction by using TEMPO in air as an environmentally benign oxidant. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C3 position of indoles.