Controlled introduction of allylic group to chlorosilanes

Allylation of chlorosilanes has been achieved with allylsamarium bromide, especially in a controlled manner. Thus allylation of trisubstituted chlorosilanes (R3SiCl) afforded a variety of aryl, aralkyl, and alkenyl substituted allylsilanes. Dichlorosilanes (R2SiCl2) can either afford monoallylated silanes or diallylated silanes depending on the amount of allylsamarium bromide used. Similarly, trichlorosilanes (RSiCl3) can selectively afford mono-, di-, and tri-allylation products. Finally, perchlorosilane (SiCl4) was allylated stepwise and the corresponding silanes containing one, two, three or four allylic groups, respectively, were obtained in satisfactory yields.