Аннотация:It is shown that the interaction of heteroatoms can strongly influence the conformational behavior of 3, 7, 9-heteroanalogs of bicyclo[3.3.1]nonane. X-ray data allow to establish the coordinates of nonhydrogen atoms, bond lengths, and valent angles for the compounds synthesized. As shown, the substitution of sulfide atom of sulfur in 9-oxa-3,7-dithiabicyclo[3.3.1]nonane for the sulfoxide atom with the formation of 3-oxo-9-oxa-analog results in the change in the conformational behavior: more stable conformation becomes ″chair-chair″ one.