Electrophilic addition to styrylsilanes: sequential carbon-carbon bond forming reactions

The replacement of the usual electron donating alkyl groups on silicon, with electronegative chloride ligands, changes the mechanism and outcome of the reaction of (E)-β-dichlorobenzylsilyl)styrene with proton and carbon electrophiles. Electrophilic addition rather than the usual substitution occurs, so that the silicon remains intact to mediate further chemical reactions. The experimental results show that Friedel-Crafts reactions of the silylated alkene are subject to the same limitations observed for non-silylated alkenes; the extent of polymerization increases as the stability of the carbenium ion decreases.