Tributylphosphine → 4-[1-(4'-Trifluoromethyl-biphenyl-4-yloxy)-propyl]-benzoic acid methyl ester

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Reaction Steps

To a solution of 4-(1-hydroxy-propyl)-benzoic acid methyl ester (300 mg, 1.55 mmol) in toluene (10 mL) is added 1, 1′-(azodicarbonyl)dipiperidine (ADDP, 585 mg, 2.32 mmol) at 0° C., followed by the addition of tributylphosphine (0.58 mL, 2.32 mmol) and 4′-trifluoromethyl-biphenyl-4-ol (442 mg, 1.86 mmol). The reaction mixture is warmed up to room temperature and stirred overnight. The mixture is loaded on silica gel, eluted with hexanes with a gradient from 0% of ethyl acetate to 50% of ethyl acetate giving 4-[1-(4′-trifluoromethyl-biphenyl-4-yloxy)-propyl]-benzoic acid methyl ester. The ester product is taken into ethanol (2 mL), treated with sodium hydroxide (5N aqueous, 1 mL) for 3 hours at room temperature. The mixture is concentrated, diluted with ethyl acetate, acidified with 5 N HCl (1.1 mL), extracted with ethyl acetate. The organic layers are dried and concentrated giving 4-[1-(4′-trifluoromethyl-biphenyl-4-yloxy)-propyl]-benzoic acid (570 mg).

Provenance & Evidence