Regioselective and stereoselective oxidation of thiacalix[4]arene tetraacetate: synthesis of all possible sulfinylcalix[4]arenes

Thiacalix[4]arene tetraacetate in the cone conformation was used as the starting point for regio- and stereoselective oxidation. Using various oxidation agents, all corresponding sulfinyl (mono-, di-, tri-, tetra-) and appropriate tetrasulfonyl derivatives were prepared and characterised by spectral methods. The pinched cone—pinched cone interconversion of tetrasulfonylcalix[4]arene was studied using dynamic 1H NMR spectroscopy.