Intramolecular Reactions of Tethered Furan‐Based Bis(p‐quinodimethanes)
Tethered bis-2,5-dimethylene-2,5-dihydrofurans were generated in the gas phase by flash vacuum pyrolysis (FVP) of diester precursors. These furan-based bis(p-quinodimethanes) are shown to undergo reactions leading to macrocycles. The observed products strongly support a mechanism involving cyclic diradical intermediates. Formation of the furan-based p-quinodimethane and the corresponding cyclization chemistry was studied by high-level ab initio calculations. The theoretical studies reveal the importance of the entropy-driven elimination steps in the high-temperature FVP chemistry.