Silylmetal reagents

Halogen-free solutions may be obtained by cleavage of a disilane with elemental lithium or methyllithium, or by reaction of disilylmercury compounds with lithium. Other methods of preparation have been reviewed1, and this same source discusses the Grignard-like reactions of silyllithium and other silylmetal reagents. 

Other silylcuprate reagents have also been used to prepare allylsilanes from allylic halides, acetates, and urethanes. Moreover, other silylmetal reagents have been... 

Extremely efficient and convenient ways to prepare alkenyl- and alkylsilanes are transition metal-catalyzed silylation of alkynes and alkenes respectively. A general mechanistic scheme should involve oxidative addition of Si-X (X = H, B, C, Si, Sn, S, and halgen) bonds to transition metal catalysts M followed by insertion of unsaturated bonds into either Si-M or X-M (M = transition metal) bond and reductive elimination (Scheme 3-22). On the other hand, highly reactive silylmetal reagents such as silylzincates and silylcuprates effect similar transformation without the aid of transition metal catalysts. 

Carbonylate anions are the most suitable starting material for the synthesis of silylmetal compounds. A prerequisite for the preparation of compounds with a formal M = Si double bond is the use of metallate dianions like Na2Fe(CO)4 (Collman s reagent) together with the respective dichlorosilanes [96]. 

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