Heteroorganic betaines 3. * Reactions of betaines containing the +P-C-Si-S- fragment

Article abstract of DOI:10.1007/BF02494721

The [Ph₃P⁺-CMe₂-SiMe₂-SEt]Br^- salt was prepared by the reaction of betaine Ph₃P⁺-CMe₂SiMeR-S^- (1a: R = Me) with EtBr. Acetylation of betaine 1a or Et₃P⁺-CHMeSiMe₂-S^- (2a) afforded 2,2,6-trimethyl-1,3-dioxa-2-silacyclohex-5-ene-4-thione Me₂SiOC(=S)CH=C(Me)O or the [Et₃P⁺-CHMeSiMe₂Cl]Cl^- salt depending on the reagent ratio. The reactions of betaines 1a,b (1b: R = Ph) or 2 with compounds (R₃Sn)₂X (X = O or NMe) can be used for the generation of silanones [RMeSi=O] and silaneimines [RMeSi=NMe] in solutions. The reactivity of betaines Ph₃P⁺-CHR¹SiMeR²-S^- (R¹ = H or Me and R² = Me or Ph) is determined by the equilibrium between the zwitterionic and ylide Ph₃P=CR¹SiMeR²SH tautomers that exist in solutions.