Abstract tert-Butyllithium/N,N,N′,N′-tetramethylethylenediamine (TMEDA) complex reacts with trimethylchloro- and trimethylbromosilanes to give mixtures of the coupling product tert-butyltrimethylsilane (I) and metalation products 1-chloro-1,1,3,3,3-pentamethyldisilmethylene (II) and 1-bromo-1,1,3,3,3-pentamethyldisilmelene, respectively. Trimethylfluorosilane and tert-butyllithium/TMEDA give only (I). Compound (I) is also the major product when methoxytrimethylsilane is treated with tert-butyllithium/TMEDA, but ethoxytrimethylsilane gives predominantly the metalation product 1-ethoxy-1,1,3,3,3-pentamethyldisilmethylene (IV). Acetoxytrimethylsilane and tert-butyllithium/TMEDA give, ultimately, 2-(trimethylsiloxy)-3,3-dimethyl-1-butene (VII). Hexamethyldisiloxane is metalated by tert-butyllithium in pentane to give LiCH2SiMe2OSiMe3, which in the presence of TMEDA rearranges to give LiOSiMe2CH2SiMe3. The difunctional silanes, dimethyldichlorosilane and dimethyldiethoxysilane, react with tert-butyllithium/TMEDA complex to give only the coupling products tert-butyldimethylchlorosilane and tert-butyldimethylethoxysilane (VI).