Facile Intramolecular Cyclization Reactions of Aromatic Ethers with Cationoids in Triptycene Systems

Abstract
1,4-Dimethoxytriptycenes were found to give cyclic ethers with unusual ease when a substituent at the bridgehead bears a cationoid center. The easy reaction is attributed to the extreme proximity between the methoxyl group and the cationic center. Mechanisms involving a cyclic oxonium ion and subsequent attack by an anion to produce the cyclic ether and a methyl derivative are discussed.