Abstract A kinetic study has been made of the reaction of some 1-organosilatranes with aqueous-methanolic hydrochloric acid. The reaction is of first-order in both silatrane and acid, and for XC 6 H 4,-silatranes electron release by X assists the reaction. For acid catalysis in water or in water/dioxan, the rate is effectively the same irrespective of whether protium oxide or deuterium oxide is used. It is suggested that the rate-determining step ...