Sila-metalation route to hydrido(trialkylsilyl)silyllithiums

The proton abstraction (sila-metalation) of trialkylsilyl-substituted dihydridosilanes with t-BuLi or LDA in THF was found to be a convenient route to the corresponding silyllithiums (RR′SiHLi; 1a, R, R′ = t-BuMe₂Si; 1b, R, R′ = Me₃Si; 1c, R, R′ = i-Pr₂MeSi; 1d, R = t-BuMe₂Si, R′ = 4-methylphenyl). Hydridosilylithium 1a was isolated as air- and moisture-sensitive, but thermally stable, colorless crystals. X-ray analysis has shown that 1a is dimeric in the solid state, where two lithium atoms bridge between anionic silicon atoms forming a parallelogram, each lithium atom is coordinated by one THF molecule, and the Si-H hydrogen atoms are in the plane of the parallelogram. X-ray analysis has shown that (t-BuMe₂Si)₂GeHLi (5) has a dimeric structure similar to that of 1a.