Highly selective methyl transfer from methylsilanes to phenylthallium(III) crown ether complexes

Article abstract of DOI:10.1021/om00025a007

Reactions of (18-crown-6)phenylthallium(III) diperchlorate monohydrate (1a) with Me₃SiR (R = PhCH₂, Et, Ph, CH=CH₂, SiMe₃, OSiMe₃) proceeded at 60°C to provide (18-crown-6)phenylmethylthallium-(III) perchlorate (3) in good to excellent yields. Cleavage of the Me-Si bond in tetramethylsilane using 1a also occurred at 25°C, albeit for a long reaction time. The silicon-containing products of the reaction of 1a with benzyltrimethylsilane were siloxanes. Intramolecular trapping of the silyl fragment by a hydroxy group using (1,7-DTC)phenylthallium(III) bis(trifluoromethane-sulfonate) (1b) was employed with trans-2-((trimethylsilyl)methyl)-1-cyclohexanol, affording a bicyclic silyl ether in 92% yield.