Enantioselective Construction of Polycyclic Indazole Skeletons Bearing Five Consecutive Chiral Centers through an Asymmetric Triple-Reaction Sequence.

A novel approach for the asymmetric construction of polycyclic indazole skeletons via enamine-imine activation and PCET activation was developed by merging organocatalysis with photocatalysis through an asymmetric triple-reaction sequence. In this process, five C-X bonds and five consecutive chiral centers were efficiently constructed. Differently substituted polycyclic indazole deriatives were successfully constructed with satisfactory results under mild conditions.