Desilylation versus elimination reactions of β-hydroxysilanes: effect of substituents on silicon

β-Hydroxy(trimethyl)silanes undergo stereospecific desilylation reactions to give alcohols using KOt-Bu in DMSO:H2O, but the reactions are very slow. In this work, desilylation reactions are facilitated using β-hydroxysilanes with (i-PrO)Me2Si, HMe2Si, or HOMe2Si groups (e.g. 9→11). The (HO)Me2Si compound (10) (or alkoxide) was shown to be an intermediate, and undergoes β elimination less readily than the Me3Si compound (7).