A theoretical study on the conformational interconversions in 1,3-dithiane 1,1-dioxide (1,3-dithiane sulfone) has been carried out. Nineteen conformations have been considered. Four minima and five transition states have been identified. A description of the inversion-topomerization process of 1,3-dithiane sulfone is presented. Calculations show that two transition states are associated with inversion and three more with topomerization. IGLO calculations of the (1)J(C-H) one-bond coupling constants in 1,3-dithiane sulfone have also been carried out. These constants are compared with those obtained for 1,3-dithiane, thiane, and thiane sulfone and their magnitude is explained in terms of stereoelectronic interactions.