para-Bridged symmetrical pillar[5]arenes: their Lewis acid catalyzed synthesis and host-guest property

J Am Chem Soc. 2008 Apr 16;130(15):5022-3. doi: 10.1021/ja711260m. Epub 2008 Mar 22.

Abstract

Condensation of 1,4-dimethoxybenzene (DMB) with paraformaldehyde in the presence of BF3.O(C2H5)2 gave novel para-bridged pentacyclic pillar DMB (DMpillar[5]arene). Moreover, para-bridged pentacyclic hydroquinone (pillar[5]arene) was prepared. Pillar[5]arene formed 1:1 host-guest complexes with dialkyl viologen and alkyl pyridinium derivatives. However, pillar[5]arene did not form complexes with the diadamantyl viologen derivative since a bulky adamantyl group was unable to thread the cavity of pillar[5]arene.