Chiral Phosphoric Acid-Catalyzed Asymmetric Friedel-Crafts Addition of Indolizine to Cyclic N -Sulfonyl Imine.

A highly efficient chiral phosphoric acid-catalyzed enantioselective Friedel-Crafts addition of indolizine to cyclic N -sulfonyl imine has been established. The newly developed protocol, which probably proceeds via a monoactivation reaction pathway, allows the access of enantioenriched sulfonamide functionalized indolizines with excellent yields (up to 99%) and enantioselectivities (up to 99%). Moreover, the synthetic utility of this protocol has been explored with some chemical transformations.