A New Route to Macrocycles Possessing the 2,6‐Pyridino Subunit via Bis‐1,3‐Dithianes [1]

Two rigid crown ethers 12, which possess a terpyridine subunit, are herein prepared by the construction of the middle pyridine moiety via a bis‐dithiane precursor. The intermediate diketone and derivatives are sufficiently mobile to permit macrocyclization; then their irreversible conversion to a pyridine nucleus circumvents the inherent structural constraints associated with the synthesis of these macromolecules.