Catalytic asymmetric Friedländer condensation to construct cyclobutanone-fused quinolines with a quaternary stereogenic centre

An enantioselective Friedländer condensation process between 2-aminobenzophenone and prochiral cyclobutane-1,3-dione has been developed to construct cyclobutanone-fused quinolines with quaternary stereogenic centers in up to 98% yield and 94% ee valve.