Addition of alkylchlorosilanes to unsaturated compounds in presence of chloroplatinic acid

Abstract

1. In the competing addition of silanes to ethylene in presence of H2PtCl6 the activity of the silanes is determined both by the inductive effect and the steric effect of the silyl groups, but the influence of the steric factor is greater than when the catalyst is platinum on a support. 2. Substituents have a deactivating influence on the ability of the double bond of an unsaturated compound to add on silanes in presence of H2PtCl6 and supported Pt. This is evidently also associated with the steric and inductive influence of these substituents. 3. The facts now known about the addition of silanes to unsaturated compounds in presence of both H2PtCl6 and supported Pt are better explained by the assumption of a specific radical mechanism rather than an ionic reaction mechanism. The specificity of this process is associated with the role of the catalyst surface or of complex-forming forces. 4. On the basis of the addition of silanes to unsaturated compounds in presence of H2PtCl6 and supported Pt, a convenient and high-yielding method of synthesis of a series of silicoorganic compounds of practical importance was developed.