Kinetic Study on the Reaction of (Arylthio)trimethylsilanes with Phenacyl Bromide Giving Aryl Phenacyl Sulfides and Bromotrimethylsilane

Abstract A kinetic study has been conducted on the reactions of (arylthio)trimethylsilanes with phenacyl bromide giving aryl phenacyl sulfides and bromotrimethylsilane. Remarkably large positive substituent effect (ρ=+2.2) and large negative entropy of activation were observed for the reaction. A mechanism involving 5-coordinated silicon intermediate prior to the rate-determining heterolysis of the Si–S bond has been suggested for the reaction based on the kinetic results.