A versatile synthon with formyl and allyl groups at the upper rim of calixarene has been synthesized in two steps. Selective formylation of 25,27-diallyloxy-26,28-dihydroxycalixarene, along with the Claisen rearrangement of the allyl groups, was achieved by reaction with hexamethylenetetraamine (hexamine) in glacial acetic acid. A control reaction of the dipropyl analogue shows that the selective formylation takes place independently of the Claisen rearrangement. The crystal structure of the dimethylacetal derivative of 5,17-diformyl-11,23-diallylcalixarene is reported.
Mocerino, M., Ogden, M. I., Pettersen, J. K., Skelton, B., & White, A. (2006). One-pot Selective Formylation and Claisen Rearrangement on Calixarenes. Supramolecular Chemistry, 18(2), 91-95. https://doi.org/10.1080/10610270500419072