Improved synthesis of aryltriethoxysilanes via palladium(0)-catalyzed silylation of aryl iodides and bromides with triethoxysilane

The scope of the palladium-catalyzed silylation of aryl halides with trieth oxysilane has been expanded to include aryl bromides. A more general Pd(0) catalyst/ligand system has been developed that activates bromides and iodid es: palladium(0) dibenzylideneacetone (Pd(dba)(2)) is activated with 2-(di- tert-butylphosphino)biphenyl (Buchwald's ligand) (1:2 mol ratio of Pd/phosp hine). Electron-rich para- and meta-substituted aryl halides (including unp rotected aniline and phenol derivatives) undergo silylation to form the cor responding aryltriethoxysilane in fair to excellent yield; however, ortho-s ubstituted aryl halides failed to be silylated.