反应详情

温度

-65 °C

The ester from Step 2 (29.1 g, 140 mmol) was dissolved in CH2Cl2 (170 mL) and cooled to −65° C. The reaction was treated with a 1.0 M solution of boron tribromide in CH2Cl2 (180 mL, 180 mmol). The reaction was stirred at −65° C. for 1.6 hours, then the cooling bath was removed and the reaction was warmed to room temperature. The reaction was added to ice water and the layers were separated. The organic layer was concentrated in vacuo, dissolved in ethyl acetate, washed with saturated NaHCO3, brine, dried over MgSO4 and concentrated in vacuo, to give methyl 2-(3-hydroxyphenyl)-2-methylpropionate as a brown oil (10.6 g, 42%): 1H NMR (CDCl3/300 MHz) 7.19 (m, 1H), 6.90 (d, 1H, J=7.9 Hz), 6.84 (m, 1H), 6.75 (d, 1H, J=8.1 Hz), 3.66 (s, 3H), 1.56 (s, 6H). The saturated NaHCO3 layer was acidified with concentrated HCl, extracted with ethyl acetate washed with the, dried over MgSO4 and concentrated in vacuo, to give 2-(3-hydroxyphenyl)-2-methylpropionic acid as a brown oil (15.8 g, 42%): 1H NMR (CDCl3/300 MHz) 7.20 (m, 1H), 6.97 (dd, 1H, J=7.9 Hz, 0.8 Hz), 6.88 (m, 1H), 6.75 (dd, 1H, J=8.1 Hz, 0.8 Hz), 1.57 (s, 6H).

1. customthe cooling bath was removed
2. temperaturethe reaction was warmed to room temperature
3. additionThe reaction was added to ice water
4. customthe layers were separated
5. concentrationThe organic layer was concentrated in vacuo
6. dissolutiondissolved in ethyl acetate
7. washwashed with saturated NaHCO3, brine
8. dry with materialdried over MgSO4
9. concentrationconcentrated in vacuo