Sodium borohydride → 2,2-Dimethyl-2,3-dihydrobenzofuran-3-ol

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Reaction Steps

To a solution of 2,2-dimethyl-benzofuran-3-one (1.58 g, 9.7 mmol) in methanol (30 mL) at 0° C. is added NaBH4 (0.36 g, 9.7 mmol). The reaction is placed at room temperature and another equivalent of NaBH4 (0.36 g, 9.7 mmol) is added. After three hours the reaction is quenched with saturated aqueous NH4Cl. The reaction is concentrated to approximately ¾ of its original volume, diluted with ethyl acetate, and washed with 2N aqueous HCl, followed by brine. The organic layer is dried with Na2SO4, filtered, and concentrated. The resulting residue is purified by silica gel flash chromatography (ethyl acetate-heptane, 0:1 to 1:8) to provide 2,2-dimethyl-2,3-dihydro-benzofuran-3-ol; 1H NMR (400 MHz, CDCl3) δ ppm 1.34 (s, 3 H), 1.49 (s, 3 H), 1.96 (d, J=8.6 Hz, 1 H), 4.71 (d, J=8.6 Hz, 1 H), 6.79 (d, J=8.1 Hz, 1 H), 6.87-6.95 (m, 1 H), 7.21-7.26 (m, 1 H), 7.39 (d, J=7.3 Hz, 1 H).

Provenance & Evidence