CRYSTAL AND MOLECULAR-STRUCTURE OF A CHIRAL CALIXARENE - (+)5,11,17,23-TETRA-TERT-BUTYL-25,27-DI[(CAMPHORSULFONYL)OXY]-26,28-DIHYDROXYCALIX[4]ARENE

Treatment of p-tert-butylcalix[4]arene with (+) camphorsulfonyl chloride in pyridine allows the synthesis of the title compound. It crystallizes in the triclinic space group P1 with a=14.671(4), b=17.530(3), c=13.085(9)Angstrom, alpha=103.69(3), beta=111.37(4), gamma=84.60(2)degrees; d(calc)=1.172 g/cm(3). Refinement on 17295 reflections; final R value of 0.084. The asymmetric unit contains two independent molecules, both in a cone conformation. The calixarene cavities have a pseudo C-2v symmetry with the two opposite phenolic rings bearing the camphorsulfonyl groups almost parallel to one another. The norborane skelton of the (+) camphorsulfonyl group is similar to the ones found in literature. The shortest intermolecular contacts concern oxygens of the camphorsulfonyl group.