Calix[4, 5]tetrolarenes: A New Family of Macrocycles

The
facile and efficient one-step synthesis and the full characterization
of novel π-electron rich macrocycles, calix-[n]­tetrolarenes (n = 4, 5), are described. The tetramer
and the much rarer sized pentamer were easily prepared by reaction
of the commercially available, partially methylated 1,2,3,5-benzenetetrol
with paraformaldehyde under TFA catalysis, with a total isolated yield
of 73%. The reaction is solvent sensitive, and the number of methylated
oxygens also affects the tetramer/pentamer distribution. The compounds
formed may be considered as “chimeric” macrocycles of
calixarene and pyrogallol­[n]­arene that may serve
as new building blocks in host–guest and supramolecular chemistry.