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

Abstract β-Hydroxy( trimethyl )silanes undergo stereospecific desilylation reactions to give alcohols using KO t -Bu in DMSO:H 2 O, but the reactions are very slow. In this work, desilylation reactions are facilitated using β-hydroxysilanes with ( i -PrO)Me 2 Si, HMe 2 Si, or HOMe 2 Si groups (e.g. 9 → 11 ). The (HO)Me 2 Si compound ( 10 ) (or alkoxide) was shown to be an intermediate, and undergoes β elimination less readily than the Me 3 Si compound ( 7 ).