Organocatalytic Asymmetric Friedel-Crafts Reaction of Sesamol with Isatins: Access to Biologically Relevant 3-Aryl-3-hydroxy-2-oxindoles
作者:Akshay Kumar、Jasneet Kaur、Pankaj Chauhan、Swapandeep Singh Chimni
DOI:10.1002/asia.201301546
日期:2014.5
The Friedel–Crafts reaction of electron‐rich phenols with isatins was developed by employing bifunctional thiourea–tertiary amine organocatalysts. Cinchona alkaloid derived thiourea epiCDT‐3 a efficiently catalyzed the Friedel–Crafts‐type addition of phenols to isatin derivatives to provide 3‐aryl‐3‐hydroxy‐2‐oxindoles 7 and 9 in good yield (80–95 %) with good enantiomeric excess (83–94 %). Friedel–Crafts
富电子酚与靛红的Friedel-Crafts反应是通过使用双官能硫脲-叔胺有机催化剂开发的。金鸡纳生物碱衍生的硫脲Epi CDT- 3 a有效地催化了苯酚在Isatin衍生物中的Friedel-Crafts型加成反应,从而以良好的收率(80-95%)提供了3-芳基-3-羟基-2-氧吲哚7和9。对映体过量(83–94%)。将Friedel-Crafts加合物7 t进行铜(I)催化的叠氮化物-炔烃环加成反应,得到对映异构体过量且具有1,2,3-三唑的具有重要生物学意义的3-芳基-3-羟基-2-氧吲哚11部分。