p-(benzyloxy)calix[8]arene: One-pot synthesis and functionalization

The condensation of hydroquinone monobenzyl ether in the presence of several bases gives a mixture of cyclic oligomers. Using p-benzyloxyphenol, paraformaldehyde, and NaOH in 45:82:1 molar ratio in refluxing xylene, p-(benzyloxy)calix[8]arene (2) was selectively produced in 48% isolated yield. Compound 2 was also functionalized at the lower rim with acetoxy, methyl, pentyl, [(ethyloxy)carbonyl]methyl, and [(N,N-diethylamino)carbonyl]methyl groups. Replacement of the benzyl groups on these compounds allowed for the first time the high-yield syntheses of calix[8]hydroquinone and its derivatives.