Carbon Dioxide → 4-(Trimethylsilyl)benzoic acid

To 1-bromo-4-(trimethylsilyl)-benzene (Aldrich) (6.42 g, 28.04 mmol) in a clean, dry 250 mL round-bottom flask was added THF (100 mL) and the mixture was cooled to −78° C. with stirring for 10 minutes under nitrogen. Then, a 2.5M solution of n-butyllithium in hexanes (13.46 mL, 1.2 eq) was added slowly over about seven minutes. The resulting mixture was stirred at −78° C. for 1.5 hours (solution turned light yellow). Then, at −78° C. an excess of dry ice (4 large pieces) were added to the reaction mixture (solution turned color, then became clear) and the dry ice bath was removed and stirred for 15 minutes. TLC confirmed that the reaction was complete, and after stirring an additional 10 minutes at −78° C., the reaction was quenched with water (100 mL). Ethyl acetate (500 mL) was then added and with stirring 4N HCl was added to pH=2. The layers were separated and then washed the ethyl acetate layer with brine (1×250 mL) and finally the organic layer was dried over magnesium sulfate, filtered, concentrated and pumped to give 4-Trimethylsilanyl-benzoic acid as a white solid (5.49 g).