Triquinane-derived macrocyclic lactones and a [2]-catenane: synthesis and characterization

Abstract

cis,syn,cis-Triquinane diol 1, with its folded topology, hydrophobic posterior and inwardly directed endo,endo-hydroxy groups, readily enters into cyclooligomerization reaction with terephthaloyldichloride 4. As many as nine cyclic oligomers A-I, with macrocyclic ring size varying from 28- to 98-membered, have been isolated and characterized. The cyclic oligomers exhibit interesting spatial relationships through the relative orientation of methylene groups on the central five membered ring of the triquinane moiety. Employing X-ray crystallography and symmetry considerations, in conjunction with NMR data, stereostructures of dimers 5 and 6, trimers 7 and 8 and tetramers 9-12 could be delineated. The crystal packing in the case of 5, 6 and 7 shows some interesting motifs and many short C-H...O contacts. From the reaction of 1 and 4, a novel [2]-catenane 16, constituted through aromatic spacers and a bulky triquinane entity, has also been isolated and characterized, through the incisive analysis of the mass spectral data.