Enantioselective Synthesis of an All-Carbon Quaternary Stereocenter by Chiral Brønsted Acid-Catalyzed Friedel–Crafts-Type Reaction between Pyrroles and 3-Indolylmethanols

We have developed a chiral phosphoric acid-catalyzed enantioselective Friedel–Crafts alkylation reaction between pyrroles and indolylmethanols. Wide substrate scope was observed, and a chiral all-carbon quaternary center was constructed at the 3 position of indoles in high yields with high to excellent enantioselectivities (up to 99% ee).