Chiral Phosphoric Acid Catalyzed Asymmetric Friedel-Crafts Alkylation of Indole with 3-Hydroxyisoindolin-1-one: Enantioselective Synthesis of 3-Indolyl-Substituted Isoindolin-1-ones

Chiral phosphoric acids have been proven to be effective organocatalysts for the asymmetric Friedel-Crafts alkylation of indoles with 3-hydroxyisoindolin-1-ones. The corresponding products were obtained in excellent chemical yields (up to 99%) with moderate to excellent enantioselectivities (up to >99% ee after a single recrystallization). This is the first example of the catalytic asymmetric synthesis of valuable 3-substituted isoindolin-1-ones in high yields and enantioselectivities.