1,1-Dimethyl-1-silacyclopentan-3-ols are synthetised by hydroboration—oxidation or epoxidation—reduction of the corresponding silacyclopent-3-enes. In acidic media, β-silacyclopentanols give ringopening reactions. Secondary sila-β-alcohols are rearranged by Raney nickel on warming to give 1-oxa-2-sila-cyclopentanes. Thermal dehydration of tertiary β-alcohols gives a mixture of cyclenic isomers from