反应详情

To a solution of racemic 4-(1-hydroxy-3-methyl-butyl)-benzoic acid methyl ester (300 mg, 1.35 mmol) in toluene (14 mL) is added 1,1′-(azodicarbonyl)dipiperidine (ADDP, 512 mg, 2.03 mmol) at 0° C., followed by the addition of tributylphosphine (0.5 mL, 2.03 mmol) and 4′-tert butyl-biphenyl-4-ol (367 mg, 1.62 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′-tertbutyl-biphenyl-4-yloxy)-3-methyl-butyl]-benzoic acid methyl ester. The ester product is taken into ethanol (5 mL), treated with sodium hydroxide (5N aqueous, 1 mL) for 3 h at room temperature. The mixture is concentrated, diluted with ethyl acetate, acidified with 5 N HCl (1 mL), extract with ethyl acetate. The organic layers are dried and concentrated giving 4-[1-(4′-tertbutyl-biphenyl-4-yloxy)-3-methyl-butyl]-benzoic acid (400 mg).

1. concentrationThe mixture is concentrated
2. additiondiluted with ethyl acetate
3. extractionextract with ethyl acetate
4. customThe organic layers are dried
5. concentrationconcentrated