Silenes and silenoids. 9. The synthesis of polyfunctional bis(group 14)-substituted cyclopentadienes via a novel cleavage reaction of silicon-carbon bonds by chloride ion

Article abstract of DOI:10.1021/om00131a025

Group 14 substituted cyclopentadienes of the type C₅H₄(MMe₂X)(M′Me₂Y), 1 (M and/or M′ = Si or Ge, X and/or Y = Cl or Me), can be conveniently prepared in good yields by the reaction of n-butyllithium with cyclopentadienyltrimethylsilane followed by treatment with Me₂MCl₂ (M = Si or Ge). In hexane the reaction gives 1 (M = Si, M′ = Si or Ge, X = Me, Y = Cl). In THF, with excess Me₂MCl₂, an unprecedented lithium chloride catalyzed cleavage of the trimethylsilyl group occurs to give excellent yields of 1 (M and M′ = Si or Ge, X and Y = Cl). Methanolysis gives the corresponding methoxy compounds 1 (X and Y = OMe). The chloride ion cleavage reaction occurs only in THF and when the substrate bears a chlorodimethylsilyl or -germyl substituent.