Silane, trimethylvinyl

Figure 6 shows relative orbital energies of trimethylvinyl-silane and allyltrimethylsilane compared with ethylene. The fact that IP of trimethylvinylsilane is lower than that of ethylene indicates the electron-donating effect of the triaUcylsilyl group that is due to the lower electronegativity of silicon than carbon. But at the same time, the LUMO of trimethylvinylsilane is lowered. The HOMO of allyltrimethylsilane is raised relative to ethylene. These facts give the grounds that trimethylvinylsilane is susceptible to nucleophilic attack, whereas allyltrimethylsilane is reactive towards electrophiles. 

In the presence of 1, (Me3Si>2 activated by a fluoride ion from TASF smoothly reacts with vinyl iodides at room temperature (r.t.), affording the corresponding trimethylvinyl-silanes in moderate to high yields with stereochemical retention (Scheme This method is applicable to the preparation of aryltrimethylsilanes from aryl iodides. Bimetallic compounds having Si—A1 and Si—Mg bonds can also be utiUzed for Pd-catalyzed silylation of vinyl electrophiles (Scheme... 

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