Facile Synthesis of Chiral Spirooxindole-Based Isotetronic Acids and 5-1<i>H</i>-Pyrrol-2-ones through Cascade Reactions with Bifunctional Organocatalysts
作者:Wengang Guo、Xu Wang、Boyu Zhang、Shuai Shen、Xin Zhou、Peng Wang、Yan Liu、Can Li
DOI:10.1002/chem.201402945
日期:2014.7.7
organocatalyzed asymmetric cascade reactions have been developed for the facile synthesis of chiral spirooxindole‐based isotetronic acids and 5‐1H‐pyrrol‐2‐ones.The asymmetric 1,2‐addition reactions of α‐ketoesters to isatins and imines by using an acid–base bifunctional 6′‐OH cinchona alkaloid catalyst, followed by cyclization and enolization of the resulting adducts, gave chiral spiroisotetronic acids and 5‐1H‐pyrrol‐2‐ones
已开发出前所未有的有机催化不对称级联反应用于手性基于螺氧杂吲哚的等渗电子酸和5-1 H-吡咯-2-酮的轻松合成.α-酮酸酯与靛红和亚胺的不对称1,2加成反应酸碱双官能6'-OH金鸡纳生物碱催化剂,然后环化并烯化所得的加合物,分别以优异的光学纯度(高达98%ee)得到手性螺异电子酸和5-1 H-吡咯-2-酮)。FT-IR分析支持金鸡纳催化剂的6'-OH基团与Isatin羰基之间存在氢键相互作用,这种相互作用可能对催化剂活性和立体控制至关重要。