Water → (2R)-2-(4-bromophenyl)-3,3-difluoropropane-1,2-diol

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Reaction Steps

To a 250 mL flask charged with commercial AD-mix-beta (7 g) were added t-BuOH (25 mL) and H2O (25 mL). The mixture was stirred at room temperature to give 2 clear phases and the low phases appeared yellow orange. After cooling to 0° C., 1-bromo-4-[1-(difluoromethyl)vinyl]benzene (1.1 g, 4.7 mmol) was added at once and the mixture was stirred at approximately 4° C. overnight. A bright yellow mixture resulted. The mixture was kept at 0° C. and solid sodium sulfite (8 g, 64 mmol) was added. The mixture was warmed to room temperature and stirred for 30 min. Ethyl acetate (50 mL) was added and the organic layer was separated. The aqueous layer was extracted with ethyl acetate (2×10 mL). Combined ethyl acetate extracts were dried (Na2SO4) and concentrated. Purification by combined Flash (40 g column; eluted with hexanes—Ethyl acetate (20% -60%) in 25 min.; flow rate: 35 mL/min and collected 18 mL/fraction) yielded the title compound as a colorless oil.

Provenance & Evidence