ChemInform Abstract: Metal‐Free‐Catalyzed Oxidative Trimerization of Indoles Using NaNO2 to Construct Quaternary Carbon Centers: Synthesis of 2‐(1H‐Indol‐3‐yl)‐2, 3′‐biindolin‐3‐ones. Issue 49 (9th December 2014) - Xue, Jun; Bao, Yunhong; Qin, Wenbing; Zhu, Jiayi; Kong, Yubo; Qu, Hongen; Chen, Zhengwang; Liu, Liangxian