Miscellaneous reactions of some tris(trimethylsilyl)methylsilicon compounds

Abstract

TsiSiMe 2I (Tsi = (Me 3Si) 3C) gives TsiSiMe 2OMe on treatment with AgBF 4 in MeOH but some TsiSiMe 2F if an excess of CsF is also present. The triflates TsiSiMe 2OSO 2CF 3 and (Me 3Si) 2C(SiMePh 2(SiMe 2OSO 2CF 3) react with alkali metal salts MX to give the corresponding derivatives TsiSiMe 2X and (Me 3Si) 2C(SiMePh 2)(SiMe 2X). TsiSiMe 2OSO 2CF 3 does not react with CF 3CH 2OH. The relative rates of reaction of the halides TsiSiMe 2X with X = Cl, Br or I with KSCN in boiling MeCN are roughly 1/2.5/6, revealing a suprisingly little variation in reactivity among the halides. TsiSiPh 2I and TsiSiMePhI undergo hydrolysis in MeCn or Me 2SO to give TsiSiPh 2OH and TsiSiMePhOH, the absence of rearrangement showing that cationic intermediates are not involved. TsiSiPh 2I reacts slowly with KSCN in MeCN to give TsiSiPh 2NCS. TsiSiPh 2H reacts with IBr to give the rearranged bromide (Me 3Si) 2C(SiMePh 2)(SiMe 2Br). Under UV irradiation: (i) TsiSiPh 2I in 1-bromohexane gives the rearranged bromide (Me 3Si) 2C(SiMePh 2)(SiMe 2Br); (ii) TsiSiMe 2N 3 in MeOH undergoes solvolysis; (iii) tBu 3SiI in CCl 4 gives tBu 3SiCl and Cl 3CCCl 3, and in MeOH undergoes photocatalysed methanolysis.