Chiral bicyclic imidazolium salts as a new class of N-heterocyclic carbene precursors
作者:Yuki Matsuoka、Yasuhiro Ishida、Kazuhiko Saigo
DOI:10.1016/j.tetlet.2008.02.175
日期:2008.4
bridged chiral bicyclic imidazole with a morpholine framework was synthesized from an enantiopure 2-amino alcohol. The resultant imidazole reacted with various electrophiles, including primary and secondary alkyl halides, benzyne, and an electron-deficient aryl halide, to give the corresponding imidazolium salts. Some of the imidazolium salts were found to have potential as the precursor of a chiral N-heterocyclic
由对映体纯的2-氨基醇合成了具有吗啉骨架的AN(1)–C(5)桥接手性双环咪唑。所得咪唑与各种亲电试剂反应,包括伯和仲烷基卤化物,苯并炔和缺电子的芳基卤化物,得到相应的咪唑鎓盐。发现一些咪唑鎓盐具有作为手性N-杂环卡宾催化剂的前体的潜能。通过将烯醇和酮通过均烯酸酯和活化的羧酸酯的中间体直接环化,以对映体富集的形式(高达ee的66%)获得目标内酯。