PS-Triphenylphosphine (6.40 g, 12.03 mmol) is added to a solution of 3-(4-methoxyphenyl)-1-propanol (1.00 g, 6.02 mmol) in DCM (300 mL), followed by N,N′-di-Boc-1H-pyrazole-1-carboxamidine (1.87 g, 6.02 mmol). The reaction mixture is cooled to 4° C., and di-tert-butyl azodicarboxylate (1.39 g, 6.02 mmol) is added portionwise. The reaction is stirred for 5 minutes at 4° C., and then allowed to warm to RT. The resulting yellow suspension is stirred at RT overnight. The reaction is filtered to remove the PS-triphenylphosphine, which is rinsed with MeOH (20 mL). The combined filtrates are concentrated in vacuo to afford a colourless oil. iso-Hexane (50 mL) is added, and a fine cream solid precipitates out of solution, which is removed by filtration. The filtrate is concentrated in vacuo, and the resulting white solid is washed with iso-hexane (50 mL). The iso-hexane is concentrated in vacuo, and the resulting pale yellow oil is purified by chromatography (SiO2, EtOAc in iso-hexane, 0%-25%) to afford the title compound crude as a colourless oil. The oil is used in further reactions with no further purification. [M+H]+ 459.
