Diastereoselective Synthesis of Tetracyclic Indoles via Stepwise Annulative Skeletal Editing of Azofurans

Stepwise annulative skeletal editing of azofurans with 2‐vinylindoles is reported, enabling a Brønsted acid‐catalyzed dearomative skeletal rearrangement of azofurans and an electrophilic halogen reagent (NXS)‐mediated aminohalogenation cascade to produce 32 examples of tetracyclic indoles in good yields with excellent diastereoselectivity (>19:1 dr in all cases). Remarkably, an extended one‐pot three‐step sequence, which incorporated an additional hydrogen bromide elimination step into the above transformations, afforded tetracyclic indoles bearing an exocyclic terminal alkene motif. This protocol demonstrates a broad substrate scope and good functional‐group tolerance, enabling the transformation of planar 2D aromatic furans into 3D tetracyclic indoles with complete regio‐ and diastereoselectivities.