“…Previously, we have isolated polylithiated carbosilanes of the type Si[(CH 2 ) 3 SiMe 2 CH 2 Li] 4 by treating Si[(CH 2 ) 3 SiMe 2 CH 2 SnBu 3 ] 4 with n-BuLi in tetrahydrofuran (thf) at À78°C; the Bu 4 Sn byproduct was removed by successive washes with pentane [7]. We have now adopted this methodology to isolate 3a, 3b and 6a, 6b, since the ferrocenyl or ruthenocenyl stannanes are readily prepared and the C-Sn bond can be cleaved quantitatively to yield the appropriate lithiated metallocene.…”