Borane → 2-(4-Bromo-2-methylphenyl)ethanol

関与物質

反応条件

反応手順

(4-Bromo-2-methylphenyl)acetic acid (59 g, 258 mmol) was dissolved in THF (100 mL), and cooled in an ice-bath to 0° C. Borane (1 M in THF, 310 mL, 1.2 eq) was added dropwise. During the addition the temperature rose slowly to 20° C. After complete addition, the ice-bath was removed and stirring was continued for 2 hours. The reaction mixture was poured into sat. aq. K2CO3 (300 mL), and the obtained suspension was diluted with H2O (500 mL). The THF layer was separated and concentrated under reduced pressure. The aqueous layer was extracted with EtOAc (2×250 mL, 1×100 mL). The residue from the concentrated THF layer was dissolved in the combined organic layer, which was washed with brine. The organic layer was dried (Na2SO4), filtered, and concentrated under reduced pressure, yielding the crude product (54.6 g) as a brown oil. The crude product was purified by column chromatography (SiO2, 2 L of 30% EtOAc in heptanes, Rf=0.3). Desired fractions were combined and concentrated under reduced pressure, yielding the title compound as a yellow oil (31.6 g, 144 mmol, 56%). 1H-NMR (CDCl3, 300 MHz) δ ppm 2.3 (s, 3H); 2.68 (t, 2H); 2.82 (t, 2H); 7.07 (d, 1H); 7.30 (d, 2H).

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