One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones
Yong‐Long Zhao, Jian‐Xiong An, Fen‐Fen Yang, Xiang Guan, Xiao‐Zhong Fu, Zongqin Li, Dapeng Wang, Meng Zhou, Yuanyong Yang, Bin He
Abstract
Abstract A one‐pot approach for the asymmetric synthesis of C2‐tetrasubstituted indolin‐3‐ones from 2‐substituted indoles was developed via merging transition metal catalysis with organocatalysis. This strategy involves two processes, including CuI catalyzed oxidative dearomatization of 2‐substituted indoles using O 2 as green oxidant, and followed by an proline‐promoted asymmetric Mannich reaction with ketones or aldehydes. A series of C2‐tetrasubstituted indolin‐3‐ones were obtained in 35–86% yields, 2:1‐>20:1 dr and 48–99% ee. Moreover, the synthetic 2‐tetrasubstituted indolin‐3‐ones could be easily transformed into 1 H ‐[1,3] oxazino [3,4‐ a ]indol‐5(3 H )‐ones via a [4+1] cyclization process. In addition, the synthetic compound 3 s show certain antibacterial activity against S. aureus ATCC25923 and multi‐drug resistance bacterial strain of S. aureus (20151027077) and its MIC values up to 8 μ g/mL and 16 μ g/mL, respectively. magnified image