Asymmetric Friedel-Crafts Reaction of 4,7-Dihydroindoles with Nitroolefins by Chiral Brønsted Acids under Low Catalyst Loading
作者:Yi-Fei Sheng、Gong-Qiang Li、Qiang Kang、An-Jiang Zhang、Shu-Li You
DOI:10.1002/chem.200900033
日期:2009.3.23
Slowly does it! By adding the substrate by a syringe pump, a highly efficient Friedel–Crafts reaction of 4,7‐dihydroindoles with nitroolefins was realized with 0.5 mol % of a chiral phosphoric acid. The Friedel–Crafts alkylation, together with a subsequent oxidation of the product, led to 2‐substituted indoles in excellent enantiomeric excesses, which can be easily transformed to enantioenriched t
慢慢来!通过使用注射泵添加底物,可以用0.5 mol%的手性磷酸实现4,7-二氢吲哚与硝基烯烃的高效Friedel-Crafts反应。Friedel-Crafts烷基化反应以及随后的产物氧化,导致对映异构体过量存在的2个取代的吲哚,很容易转化为对映体富集的四氢-γ-咔啉。