Syntheses and Reactivities of Stable Halosilylenoids, (Tsi)X ₂SiLi (Tsi = C(SiMe₃)₃, X = Br, Cl)

Halosilylenoids, stable at room temperature (Tsi)X₂SiLi (Tsi = C(SiMe₃)₃, X = Br, Cl), were synthesized from the reaction of TsiSiX₃ with lithium naphthalenide. Bromosilylenoid reacted with tBuOH and MeI both at -78°C and at room temperature to give (Tsi)HSiBr₂ and (Tsi)MeSiBr₂, respectively, in high yields; this clearly shows its nucleophilicity. In the reaction of bromosilylenoid with methanol, 2-propanol, and 2,3-dimethyl-1,3-butadiene, the corresponding products, (Tsi)HSi(OMe)₂, (Tsi)HSi(OiPr)Br, and bromo(Tsi)silacyclopent-3-ene, were obtained in high yields; this demonstrates its amphiphilic property, as if bromosilylene would be trapped. Chlorosilylenoid also exhibited both nucleophilic and amphiphilic properties. The ²⁹Si chemical shifts for (Tsi)Br₂SiLi, (Tsi)Br ₂SiK, and (Tsi)Cl₂SiLi were 106, 70, and 87 ppm, respectively.