CuI-Catalyzed Aerobic Oxidative α-Aminaton Cyclization of Ketones to Access Aryl or Alkenyl-Substituted Imidazoheterocycles
作者:Yuanfei Zhang、Zhengkai Chen、Wenliang Wu、Yuhong Zhang、Weiping Su
DOI:10.1021/jo402134x
日期:2013.12.20
CuI-catalyzed aerobic oxidative synthesis of imidazoheterocycles has been achieved. Four hydrogen atoms were removed in one step. This protocol was compatible with a broad range of functional groups, and it has been also successfully extended to unsaturated ketones, bringing about the formation of alkenyl-substituted imidazoheterocycles, which were difficult to prepare by previous means. Preliminary mechanistic studies indicated that this reaction was most likely to proceed through a catalytic Ortoleva-King reaction. By using this method, the marketed drug Zolimidine could be prepared with 90% yield on a gram scale from commercially available materials.
Catalyst- and oxidant-free electrooxidative site-selective [3/4 + 2] annulation to fused polycyclic heteroaromatics
Herein, a straightforward electrochemical oxidation [3 + 2] or [4 + 2] annulation of imidazo[1,2-a]pyridines with alkynes to heterocyclic aromatic compounds under metal- and exogenous oxidant-free conditions has been accomplished. This green and sustainable methodology features excellent regioselectivity, wide substrate adaptability and good functional group compatibility. Moreover, a possible mechanism