Hydrochloric Acid → m-Ethynylphenol

Participants

Reaction Steps

To a stirred solution of PdCl2(PPh3)2 (46 mg, 0.04 mmol), CuI (15 mg, 0.08 mmol), and Et3N (0.303 g, 0.42 mL, 3 mmol) in 10 mL of THF under nitrogen was added 3-iodophenol (0.440 g, 2 mmol) by syringe. The reaction mixture was cooled to 0° C., and trimethylsilylacetylene (0.206 g, 0.30 mL, 2.1 mmol) was added dropwise over 30 min. The reaction mixture was stirred at room temperature overnight and was filtered through Celite to remove Pd and Cu catalysts. Column chromatography (n-hexane/Acetone 6:1) yielded 3-(2-(trimethylsilyl)ethynyl)phenol (380 mg, 2.0 mmol, >99%) as a light brown oil. This compound was diluted with THF (6 mL) and MeOH (6 mL), and 10% aqueous KOH (6 mL) was added. After stirring for 2 hr, the reaction mixture was neutralized by 1 N HCl and evaporated, extracted with CH2Cl2, and dried (Na2SO4). Column chromatography (n-hexane/acetone 5:1) yielded 3-ethynylphenol (162.8 mg, 70%) as a yellow oil.

Provenance & Evidence