Secondary Deuterium Isotope Effect in an Electrophilic Aromatic Substitution- Protodesilylation of Trimethylphenylsilane

Article abstract of DOI:10.1002/hlca.19810640833

Reaction rates for the protodesilylation of trimethylphenylsilane and of <2,4,6-2H3>-trimethylphenylsilane by HClO4, were measured in aqueous methanol (2:5, v/v) and the secondary deuterium isotope effect for the reaction was found to be k_H/k_D3=0.79.The magnitude of the observed isotope effect supports a mechanism in which the rate-determining step is the proton transfer from the hydronium ion to the silane to form a ?-intermediate.