Highly Selective Copper-Catalyzed Asymmetric [3+2] Cycloaddition of Azomethine Ylides with Acyclic 1,3-Dienes
作者:María González-Esguevillas、Ana Pascual-Escudero、Javier Adrio、Juan C. Carretero
DOI:10.1002/chem.201500182
日期:2015.3.16
catalytic asymmetric 1,3‐dipolar cycloaddition of azomethine ylides with acyclic activated 1,3‐dienes (and 1,3‐enynes) are described. Under copper catalysis, a selective cycloaddition at the terminal γ,δ‐CC bond is observed. In addition, depending on the ligand used, either the exo or the endo adduct can be obtained with high selectivity. Under appropriate reaction conditions, the acyclic 1,6‐addition
描述了具有无环活化的1,3-二烯(和1,3-烯炔)的甲亚胺烷基化物催化不对称的1,3-偶极环加成反应的第一个例子。在铜催化下,观察到在末端γ,δ-CC键上的选择性环加成。另外,取决于所用的配体,可以高选择性地获得外型或内型加合物。在适当的反应条件下,检测到无环1,6加成产物,表明是逐步的机理。生成的C4-链烯基取代的吡咯烷是进一步进入多环系统的合适底物,如六氢色紫[4,3- b ]吡咯的制备和生物碱gracilamine的四环核心所强调的那样。