Enantioselective Synthesis of Tetrahydroindolizines via Ruthenium–Chiral Phosphoric Acid Sequential Catalysis

A chiral phosphoric acid and a ruthenium complex were found to catalyze an olefin cross-metathesis-asymmetric intramolecular Friedel-Crafts alkylation of N-tethered olefin pyrroles and conjugated enones to provide a variety of chiral tetrahydroindolizine derivatives in moderate to good yields and enantioselectivity (up to 93% ee).