Synthesis and structure of new cyclophanes containing benzofuran and benzene rings

Macrocycles 2–3 are synthesized by reacting 2,4-dihydroxybenzophenone with α,α′-dibromo-p-xylene and then 1,6-diiodohexane. Photoirradiation of 2 yields a new type of cyclophane 5 containing two benzo[b]furan rings via intramolecular δ-hydrogen abstraction. X-Ray analysis shows that 5 has a rectangular cavity of ca. 5.9 Å×7.6 Å.