Access to Polycyclic Indole-3,4-Fused Nine-Membered Ring via Cascade 1,6-Hydride Transfer/Cyclization

A cascade aldimine condensation/1,6-hydride transfer/Mannich-type cyclization of indole-derived phenylenediamine with aldehydes was developed for one-step construction of a polycyclic indole-3,4-fused skeleton. Aldehyde serves as a key to start the whole process, including 1,6-hydride transfer enabled delta-C(sp(3))-H activation of the secondary amine. The challenges of construction of medium-sized rings are addressed via hydride transfer chemistry.

Automated summary

This study presents a novel method for one-step construction of a polycyclic indole-3,4-fused skeleton. By involving aldehydes and hydride transfer chemistry, the challenges of constructing medium-sized rings have been successfully addressed.