Chiral phosphoric acid-catalyzed enantioselective [5+1] cycloaddition reaction of ,-cyclic azomethine imines with isocyanides.

The first catalytic enantioselective [5+1] cycloaddition reactions of -cyclic azomethine imines with isocyanides are reported herein. The method displays a broad substrate scope and atom-economy. A series of chiral tetrahydroisoquinoline containing indole skeletons were obtained in up to 90% yield with 95% ee under mild reaction conditions. A possible catalytic model was also proposed.