Conformational behaviour of medium-sized rings. Part 8. 6H,12H,18H-Tribenzo[b,f,j][1,5,9]trithiacyclododecin and its 5,5,11,11,17,17-hexaoxide

Abstract

The temperature-dependences of the ¹H n.m.r. spectra of 6H,12H,18H-tribenzo[b,f,j][1,5,9]trithiacyclodode (7) and its 5,5,11,11,17,17-hexaoxide (8) have been interpreted in terms of ring inversions between enantiomeric helical conformations. The free energy of activation for conformational inversion in the cyclic trisulphide (7) is compared with that previously obtained for the ring inversion of the enantiomeric C₂ conformations of the parent hydrocarbon 5,6,11,12,17,18-hexahydrotribenzo[a,e,i]cyclododecene (1).