Facile Synthesis of p-Phenyl Homooxacalix[4]arenes

Calixarenes are synthetic macrocycles available in a vari-ety of ring sizes and are of interest both as complexation hosts for ions and molecules and as frameworks for elaborat-ing more complex structures and have received a great deal of attention in recent years.1~3 In contrast to the calix[4]are-nes, homooxacalix[4]arenes, containing extra oxygens in the macrocyclic ring, have received little attention mainly because they can only be synthesized in relatively low yield. p-t-Butyl dihomooxacalix[4]arene was obtained as a minor product (20 % yield) from the direct base-catalyzed conden-sation reaction of p-t-butylphenol and formaldehyde4 and then the yield was enhanced up to 25%.5 p-t-Butyl tetraho-modioxacalix[4]arene was prepared by Gutsche in 44% yield from the dehydration of bishydroxymethylated dimer of p-t-butylphenol in xylene.6 There have only been limite