Abstract The E/Z-isomers of 2, 4-dineopentyl-1, 3-disilacyclobutanes (R 1 R 1 SiCHCH 2 t Bu) 2 are obtained in good yields from the reaction of diorganovinylchlorosilanes R 1 R 2 Si (Cl) CH CH 2 with Li t Bu in non-polar solvents. This synthetic route becomes less attractive as the number of chlorosubstituents at the vinylsilane increases: Thus, tetrachloro- 2, 4-dineopentyl-1, 3-disilacyclobutane (2) cannot be prepared from Cl 3 SiCH CH 2 (1) ...