Regioselective Synthesis of Methylene-Bridged Naphthalene Oligomers and Their Host–Guest Chemistry

In this research, we report the regioselective synthesis of methylene-bridged naphthalene oligomers from 2,6-dialkoxyl naphthanene and paraformaldehyde by using <i>p</i>-TsOH as the catalyst and CH₂Cl₂ as the solvent. The structures were characterized by NMR spectroscopy and X-ray crystallography. Their host–guest chemistry with organic cations was studied, and optimal naphthalene numbers in the oligomers were revealed for different guests. In addition, the reason for the unsuccessful synthesis of methylene-bridged naphthalene macrocycles was discussed