Conversion of Disilanes to Functional Monosilanes. XIII. The Palladium Catalyzed Reductive Coupling of Benzylidene Dichlorides and Benzylidyne Trichlorides Using Disilanes as Reducing Agents

The reaction of benzylidene dichlorides or benzylidyne trichlorides with 1,2-dichloro-1,1,2,2-tetramethyldisilane or hexamethyldisilane proceeded smoothly in the presence of acatalytic amount of Pd(PPh3)4 to give (E)-stilbenes or (E)- and (Z)-α,β-dichlorostilbenes in high yields, respectively. Also, in the presence of the palladium(0) catalyst, α,α-dichlorobenzyltrimethylsilanes reacted with hexamethyldisilane yielding (E)-α,β-bis(trimethylsilyl)stilbenes in quantitative yield.