Efficient, Regioselective Access to Bicyclic Imidazo[1,2-<i>x</i>]- Heterocycles via Gold- and Base-Promoted Cyclization of 1-Alkynylimidazoles
作者:Christophe Laroche、Sean M. Kerwin
DOI:10.1021/jo902073m
日期:2009.12.4
derivatives followed by addition of aldehydes or ketones are presented. The method gives access to 1-alkynyl-2-(hydroxymethyl)imidazoles which undergo 6-endo-dig or 5-exo-dig cyclization under AuCl3- or base-catalyzed conditions to yield imidazo[1,2-c]oxazoles and imidazo[2,1-c][1,4]oxazine heterocycles. Under transition metal catalysis, the reaction occurs in a regiospecific manner, leading exclusively
提出了1-炔基咪唑的反应,包括它们的2-硫代衍生物的形成,然后加入醛或酮。该方法提供了在AuCl 3-或碱催化的条件下进行6-内-挖或5- exo-挖环化反应的1-炔基-2-(羟甲基)咪唑,生成咪唑并[1,2- c ]恶唑和咪唑并[2,1- c ] [1,4]恶嗪杂环。在过渡金属催化下,该反应以区域特异性方式发生,仅导致6 -endo-dig攻击的产物,而在碱性条件下,该反应以区域选择性方式发生,优先提供5 -exo-dig攻击的产物。。