反应详情

温度

-78 °C

To a solution of 5-bromo-2-chloro-benzoic acid methyl ester (5 g) in diethyl ether (200 mL) cooled to −70° C. is added 3 M methylmagnesium bromide in THF (20 mL) dropwisely. The solution is stirred at −78° C. for 2 h and allowed to warm to room temperature for 16 hours. The solution is cooled to 0° C. and 1 N HCl (100 mL) is added dropwisely. The mixture is extracted with EtOAc (2×150 mL). The combined organic layer is washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo. The residue is chromatographed on silica gel eluting with 20% EtOAc in heptane to afford 2-(5 bromo-2-chloro-phenyl)-propan-2-ol (4.56 g). MS: 250 (M+H); 1H NMR (300 MHz, CDCl3) □7.8 (m, 1H); 7.5 (m, 1H); 7.2 (m, 1H); 4.4 (s, 1H); 1.6 (s, 6H).

1. temperatureto warm to room temperature for 16 hours
2. temperatureThe solution is cooled to 0° C.
3. extractionThe mixture is extracted with EtOAc (2×150 mL)
4. washThe combined organic layer is washed with brine
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. customevaporated in vacuo
8. customThe residue is chromatographed on silica gel eluting with 20% EtOAc in heptane