Stereoelectronic interactions are too weak to explain the molecular conformation in solid state of cis -2- tert -butyl-5-( tert -butylsulfonyl)-1,3-dioxane.

cis -2- tert -Butyl-5-( tert -butylsulfonyl)-1,3-dioxane ( cis -1) exhibits a high degree of eclipsing in the H-C5-S-C segment in the solid state, the origin of which remains unexplained. The eclipsed conformation that corresponds to an energetic minimum in the solid state practically corresponds to a rotational transition state in solution, which allows an approach to understand transitions states. The difference in the enthalpy of sublimation Δ _sub H between cis -1 and the more stable trans -1 is 8.40 kcal mol ^-1 , lets to consider that the intermolecular interactions in the crystalline structure must be responsible for the conformational effect observed in the solid state. The study of the experimental electron density of cis -1 in solid state allowed to establish that CH⋯OS intermolecular interaction is the main contribution to the observed eclipsing. The charge density analysis was also performed using the quantum theory of atoms in molecules to evaluate the nature and relevance of the intermolecular interactions in the crystal structure.