Anionic 1,4-silyl migration in (2-(trimethylsilyl)phenyl)phosphonium methylides

To investigate the intramolecular 1,5-type C-center dot center dot center dot Si interaction, (2-(trimethylsilyl)phenyl)phosphonium methylides 1 were prepared. Treatment of the precursors, the methyl(2-(trimethylsilyl)phenyl)phosphonium iodides 2 (R = Ph, Me), with sodium hexamethyldisilazide in THF afforded the phosphonium methylides 1, which readily underwent anionic 1,4-silyl migration to form the silylated ylides 4 at low temperatures. They were characterized by NMR and trapping experiments.