2,5-Dichlorophenol (325 mg, 2.00 mmol) and (3-hydroxypentyl)methylcarbamic acid, 1,1-dimethylethyl ester (217 mg, 1.00 mmol) were dissolved in tetrahydrofuran (10 ml). To the resulting solution was added triphenylphosphine (393 mg, 1.50 mmol) and then diethyl azodicarboxylate (0.240 ml, 1.52 mmol). The solution was then allowed to stir at room temperature under nitrogen for 24 h. The mixture was then poured into water and extracted three times with diethyl ether. The combined organic fractions were washed with 1N sodium hydroxide solution twice and then brine and dried over magnesium sulfate. The solvent was evaporated and the residue eluted down a flash chromatography column using 10% ethyl acetate/isohexane as eluent to give 180 mg (50%) of the title compound as an oil.
