Palladium Catalysed Tandem Cyclisation–Anion Capture. Part 5: Cascade Hydrostannylation-bis-cyclisation-intramolecular Anion Capture. Synthesis of Bridged- and Spiro-Cyclic Small and Macrocyclic Heterocycles

A series of O- and N-α,ω-enyne derivatives of 2-iodoarylethers and 2-iodoarylamides undergo palladium catalysed cascade hydrostannylation of the ω-alkyne moiety at 0–25°C followed by bis-cyclisation at 100–110°C terminating in intramolecular sp3–sp2 Stille coupling. These cascades provide a wide range of 5/6 and 5/12–17 membered bicyclic spiro- and bridged-ring heterocycles.