Oxidant promoted 1,3-dipolar cycloaddition of benzimidazolium ylides to alkenes for preparation of 4<i>H</i>-pyrrolo[1,2-<i>a</i>]benzimidazole
作者:Bingxiang Wang、Jiaxin Hu、Xuechun Zhang、Yuefei Hu、Hongwen Hu
DOI:10.1002/jhet.5570370620
日期:2000.11
An oxidant promoted 1,3-dipolar cycloaddition of benzimidazolium ylides to alkenes was developed for the preparation of 4H-pyrrolo[1,2-a]benzimidazole derivatives in moderate yields under mild conditions. In the presence of a suitable oxidant, the most commercially available “normal” alkenes, instead of alkynes or “abnormal” alkenes, could be used as dipolarophiles successfully. Moreover, CrO3/Et3N
开发了一种氧化剂促进苯并咪唑鎓烷基化物与烯烃的1,3-偶极环加成反应,用于在温和条件下以中等收率制备4 H-吡咯并[1,2- a ]苯并咪唑衍生物。在合适的氧化剂存在下,最商业上可买到的“正构”烯烃,而不是炔烃或“反常”烯烃,可以成功地用作双极性亲和剂。此外,在该程序中,已证明CrO 3 / Et 3 N是比MnO 2或重铬酸四基吡啶钴(II)更为有效的脱氢剂。