Generally, non-polar solvents promote the S N 2 mechanism, whereas polar solvents facilitate the S N 1 mechanism by solvating the ions to form solvent-separated ion pairs. In DCM (with dielectric constant, ε, of 8.93), which lies in between non-polar, such as dioxane (ε= 2.25), and polar solvents, such as acetonitrile (ε= 37.5), at 223.15 K, the β-glycoside is favoured, suggesting an S N 2-like mechanism. However, this preference diminishes at 303.15 K, indicating a change to S N 1-like mechanism. This behaviour further illustrates the complexity of the competition between the reaction mechanism and the importance of an accurate description of the subtle interactions with the solvent.