Duan Xin-Fang, Ma Zi-Qian, Zhang Fang, Zhang Zhan-Bin
Department of Chemistry, Beijing Normal University, Beijing, 100875, China.
J Org Chem. 2009 Jan 16;74(2):939-42. doi: 10.1021/jo802172f.
Iodo- or 2-bromopyridine N-oxides were readily magnesiated with i-PrMgCl x LiCl via the iodine or bromine-magnesium exchange. The bromine adjacent to pyridine N-oxide (at the 2- or 6-position) can be regioselectively magnesiated in the presence of other position substituted halogens. This method was tested in various substituted pyridine N-oxide systems, and has been successfully applied to the total synthesis of caerulomycins E and A.
碘代或2-溴吡啶N-氧化物可通过碘或溴-镁交换，用异丙基氯化镁·氯化锂轻松地进行镁化反应。在吡啶N-氧化物（2-或6-位）相邻的溴，在其他位置有取代卤素存在的情况下，可进行区域选择性镁化反应。该方法在各种取代的吡啶N-氧化物体系中进行了测试，并已成功应用于铜绿霉素E和A的全合成。
