Synthesis of Bis-Benzo-12-Crown-4 Ethers

Abstract Bis-crown ethers with benzo-15-crown-5 moieties have been known to form stable sandwiched type complexes with ion pairs of potassium salts in organic solvents.1 The separation of ion pairs results in an increase of the anion reactivities in nucleophilic substitution reactions.2 Recently, we have reported the synthesis of bis-crown ethers with either benzo-15-crown-5 or benzo-18-crown-6 moieties bridged only by ether functional group.3 When these bis-crown ethers are used as phase transfer reagents in phase transfer reactions, their catalytic effects depend on the type of crown moiety.4