Unprecedented cyclisations of calix[4]arenes under the Mitsunobu protocol. Part 3: Thiacalix[4]crowns versus dimers

Intermolecular couplings versus intramolecular ring closures were observed in the reaction of p-tert-butylthiacalix[4]arene and diethylene glycols affording dimers and/or the inherently chiral 1,2-thiacalix[4]crown-3 derivatives under the Mitsunobu protocol. The enantiomeric separation of was achieved by chiral HPLC. The reaction of thiacalix[4]monocrowns with diethylene glycols failed to give crowned thiacalix-tubes , instead biscrowns were formed. Partially alkylated double thiacalix[4]arenes , were obtained via the base promoted alkylations of a thiacalixarene dimer containing diethyleneoxy linkers.