Synthesis of 5-alkyl-5-aryl-1-pyrroline N-oxides from 1-aryl-substituted nitroalkanes and acrolein via Michael addition and nitro reductive cyclization |
| |
Authors: | Jingjing Xu Xingyao Li Jinlong Wu Wei-Min Dai |
| |
Institution: | 1. Laboratory of Asymmetric Catalysis and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, China;2. Laboratory of Advanced Catalysis and Synthesis, Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China |
| |
Abstract: | A general method for accessing 5-alkyl-5-aryl-1-pyrroline N-oxides (AAPOs) has been established using readily available aryl bromides, nitroalkanes, and acrolein as the starting materials. The palladium-catalyzed arylation of nitroalkanes gave the 1-aryl-substituted nitroalkanes, which underwent the Et3N-catalyzed Michael addition with acrolein at room temperature to afford the 4-aryl-4-nitroaldehydes. The latter were then subjected to the nitro reductive cyclization using Zn–HOAc in EtOH at 0 °C followed by warming the reaction mixture to room temperature for 24 h, furnishing the 5-alkyl-5-aryl-1-pyrroline N-oxides in good overall yields. Selected examples of 1,3-dipolar cycloaddition of the cyclic nitrones with methyl methacrylate were also described. |
| |
Keywords: | Arylation Cyclization Michael addition Nitroalkanes Nitrones Palladium |
本文献已被 ScienceDirect 等数据库收录! |
|