1, 3-Butadiene reacted with chlorosilanes and Grignard reagents at 20° C in the presence of a catalytic amount of Pd (acac) 2 to give disilylated dimers 2 regioselectively, which have two silyl groups (R3Si) at the 3-and 8-positions of a 1, 6-octadiene skeleton. When phenyl-or