Potassium Carbonate → 2-Chloro-5-fluorophenylacetylene

To a solution of ((2-chloro-5-fluorophenyl)ethynyl)trimethylsilane (4.2 g, 18 mmol) in methanol (40 mL) was added potassium carbonate (7.7 g, 56 mmol), and the reaction mixture was stirred for 2 hours at room temperature. The reaction mixture was then diluted with diethyl ether (100 mL) and washed with water (300 mL). The organic layer was separated, dried over sodium sulfate, filtered, and evaporated in vacuo to afford a residue that was purified by flash chromatography (silica, 220 g, ISCO, heptane) to afford the title compound as a pale yellow, waxy solid (2.0 g, 70%), which was used in the next step without further purification.