Syntheses of aromatic bridged cryptophanes and their complexing abilities with alkyl ammonium cations

Several aromatic bridged cryptophanes were successfully synthesized. p-Xylene bridged cryptophane Anti-3 was prepared by the direct trimerization of alpha,alpha'-bis[4-hydroxymethyl-2-methoxyphenoxy]-p-xylene. The synthesis of o-xylene bridged cryptophane Anti-8 was carried out by the direct trimerization and/or the stepwise method from vanillyl alcohol. The o-[4,5-bis(methoxycarbonyl)]xylene bridged cryptophanes Anti-15a and Syn-15b were also prepared by the stepwise method from vanillyl alcohol. Anti-3 was capable of complexing with almost all the quaternary alkylammonium cations among the primary, secondary, tertiary and quaternary ammonium cations, and selectively prefered to complex with the NEt(3)Me(+) cation as a guest. From the complexation of the o-xylene bridged cryptophanes Anti-8, and the analogs Anti-15a and Syn-15b with the NMe(4)(+) cation, the cryptophanes Anti-8 and Syn-15b were confirmed to complex with the guest cation, however, Anti-15a was not confirmed to be included.