Conformational analysis of substituted 1,2-oxathiane 2-oxides by 13C and 1H nuclear magnetic resonance spectroscopy

1H and 13C nmr results for 1,2-oxathiane 2-oxide and eight derivatives are reported. It is concluded that these molecules have a high preference for chair forms with axial S=O groups, even when a sterically bulky group such as phenyl is substituted in a syn-axial orientation to the exocyclic oxygen.