Understanding fluoride exchange between aryl-trifluoroborates and aryl-trialkoxy silanes: access to benchtop aryl-aryl cross couplings.

As the most abundant metalloids on earth boron and silicon play important roles in chemistry, allowing for the synthesis of a wide array of useful small molecules and materials. Fluoride is known to react with boron and silicon atoms. Fluoride etching of silicates is a common reaction with glass materials. Fluorides readily react with arylboronic acids to yield aryltrifluoroborates which are commonly in aromatic cross coupling reactions. Herein we explore fluoride exchange between potassium aryltrifloroborates and triethoxyphenylsilane. We further explore the fluorine exchange between different phenyl boronic acids and trifluorophenylsilane. NMR analysis allows us to conclude that fluoride favors the formation of bonds to boron while silicon preferentially bonds to oxides over fluoride. Finally, we demonstrate that this fluorine exchange can be used as a molecular template to cross couple aromatic rings at room temperature.