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.