Synthesis of pillar[7]arene

The first synthesis of pillar[7]arene is reported with two methods. Method A: the FeCl3-catalyzed condensation reaction of 1,4-dimethoxybenzene (1) with paraformaldehyde in CHCl3 gave dimethoxypillar[7]arene (3). Method B: the p-toluenesulfonic acid catalyzed condensation reaction of 2,5-bis(benzyloxymethyl)-1,4-dimethoxybenzene (2) in CH2Cl2 gave compound 3. Demethylation of 3 with BBr3 gave pillar[7]arene (4). The pillar[7]arene might be a perspective macrocyclic host in host-guest chemistry. (C) 2012 De Rong Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.