Scaffold-divergent synthesis of ring-fused indoles, quinolines, and quinolones via iodonium-induced reaction cascades

N-(2-lodophenyl)imines A are readily formed from Schiff s base condensation of 2-iodoanilines with carbonyls and ketals. These imines provide useful substrates in scaffold-divergent synthesis through the attachment of an alkyne (Songashira coupling or acyl substitution of a Weinreb amide) followed by an iodonium-induced reaction cascade to give ring-fused indoles B, quinolines C, or quinolones D depending on the reaction conditions employed.