Chlorodiphenylphosphine

Typical Procedure^1a):
A toluene (10 mL) solution of 4-ethynylanisole (132 mg, 1.0 mmol), CuI (19 mg, 0.1 mmol), Ph₂PCl (265 mg, 1.2 mmol) and Et₃N (202 mg, 2.0 mmol) is stirred at 80 °C for 8 h. After workup with CH₂Cl₂ and NH₄Cl(aq), the combined organic layer is washed with brine, and dried over MgSO₄. After evaporation, the residue is purified by column chromatography on silica gel (eluent: hexane/CH₂Cl₂ = 6/1-4/1) to give ((4-methoxyphenyl)ethynyl)diphenylphosphine as pale yellow sticky gel (193 mg, 61%).
To a THF (10 mL) solution of ((4-methoxyphenyl)ethynyl)diphenylphosphine (316 mg, 1.0 mmol) is added H₂O₂(aq) (30%, 2.5 mL, 20 mmol) at 0 °C, and the mixture is stirred at rt for 2 h. After workup with CH₂Cl₂ and water, the combined organic layer is washed with brine and dried over MgSO₄. After evaporation, the residue is purified by column chromatography on silica gel (eluent: hexane/AcOEt = 2/1) to afford ((4-methoxyphenyl)ethynyl)diphenylphosphine oxide as white powder (312 mg, 94%).
To a THF solution (10 mL) of ((4-methoxyphenyl)ethynyl)diphenylphosphine oxide (166 mg, 0.5 mmol) is added t-BuOK (84 mg, 0.75 mmol), and the mixture is stirred at rt for 2 h. After workup with CH₂Cl₂ and NH₄Cl(aq), the combined organic layer is washed with brine and dried over MgSO₄. After evaporation, the residue is purified by column chromatography on silica gel (eluent: hexane) to afford 4-ethynylanisole as pale yellow oil (60 mg, 91%).

[Experimental procedure]
to a mixture of alkoxydiphenylphosphine (2, 0.60 mmol), prepared from the alcohol (1), n-BuLi and chlorodiphenylphosphine, and tetrafluoro-1,4-benzoquinone (0.72 mmol) under argon atmosphere is added a dichloromethane (0.50 mL) solution of alcohol (3, 0.72 mmol) at room temperature. After the reaction that is monitored by TLC was completed, the reaction mixture is quenched by adding water and the aqueous layer is extracted with dichloromethane. The organic layers are dried over anhydrous sodium sulfate. After filtration and evaporation, the resulted residue is purified by preparative TLC to afford the corresponding ether (4).