Abstract: | Dilithiated di(stannyl)oligosilanes (tBu2Sn(Li)– (SiMe2)n–Sn(Li)tBu2; 4 , n = 2; 5 , n = 3) were synthesized by the reaction of lithium diisopropylamide (LDA) with the α,ω‐hydrido tin substituted oligosilanes (tBu2Sn(H)– (SiMe2)n–Sn(H)tBu2; 1 , n = 2; 2 , n = 3). Surprisingly, the reaction of 1 and 3 (tBu2Sn(H)–(SiMe2)4–Sn(H)tBu2) with LDA resulted not in the formation of the lithiated compound, but what one can find is the formation of the 5,5‐ditert.butyl‐octamethyl‐1,2,3,4‐tetrasila‐5‐stannacyclopentane ( 8 ) (n = 4) in addition to the expected product 4 (n = 4) and the 3,3,6,6‐tetratert.butyl‐octamethyl‐1,2,4,5‐tetrasila‐3,6‐distannacyclohexane ( 7 ) (n = 3). Reactions of 4 and 5 with dimethyl and diphenyldichlorosilanes yielding monocyclic Si–Sn derivatives ( 9 – 11 ) are also discussed. The solid‐state structures of 7 and 11 were determined by X‐ray crystallography. |