Copper-Mediated Cascade C-H/N-H Annulation of Indolocarboxamides with Arynes: Construction of Tetracyclic Indoloquinoline Alkaloids.

An efficient and environmentally benign Cu-mediated method was developed for direct cascade C-H/N-H annulation to construct polyheterocyclic indoloquinoline scaffolds. This method highlights an emerging strategy for transforming inert C-H bonds into versatile functional groups in organic synthesis and provides a new versatile approach for the efficient synthesis of indolo[3,2-c] and [2,3-c]quinoline alkaloids.