Iridium-Catalyzed Intramolecular Asymmetric Allylic Alkylation of Hydroxyquinolines: Simultaneous Weakening of the Aromaticity of Two Consecutive Aromatic Rings

摘要

Intramolecular asymmetric allylic alkylation reactions of 5- and 7-hydroxyquinoline derivatives were realized by a chiral Ir/NHC catalyst. A series of functionalized cyclic enones were afforded in excellent yields (up to 99%) and high enantioselectivity (up to 97% ee). Theoretical computations revealed that the aromaticity of the two consecutive rings of hydroxyquinoline substrates is significantly weakened. A highly efficient formal synthesis of (−)-gephyrotoxin was accomplished based on this method.