Hydrochloric Acid → 7-bromo-5-hydroxy-3,4-dihydro-2H-naphthalen-1-one

Participants

Reaction Conditions

Reaction Steps

To a mixture of tris(dibenzylideneacetone)dipalladium(0) (210 mg, 0.23 mmol), di-tert-butyl-(2′,4′,6′-triisopropyl-biphenyl-2-yl)-phosphane (403 mg, 0.92 mmol), and potassium hydroxide (1.67 g, 25.32 mmol) were added degassed water (5.25 mL) and a solution of 5,7-dibromo-3,4-dihydro-2H-naphthalen-1-one (3.5 g, 11.51 mmol) in dioxane (7.0 mL) at room temperature under nitrogen. The resulting suspension was heated to 100° C. for 3.5 h. The reaction mixture was then cooled to room temperature, diluted with water (˜10 mL) and acidified with 1N HCl solution. The resulting mixture was extracted with ethyl acetate (2×100 mL) and the combined organic extracts were washed with brine (200 mL), then dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. The crude product was purified by chromatography, using an ISCO (120 g) column (gradient elution with 5-30% ethyl acetate in hexanes) to obtain 7-bromo-5-hydroxy-3,4-dihydro-2H-naphthalen-1-one (0.45 g, 16%) as a white solid: ES(−)-HRMS m/e calcd. (calculated) for C10H9O2Br (M−H)− 238.9713, obsd. (observed) 238.9712. Two other side products were also isolated and characterized as 5-bromo-7-hydroxy-3,4-dihydro-2H-naphthalen-1-one (0.3 g, 10%) and 5,7-dihydroxy-3,4-dihydro-2H-naphthalen-1-one (0.191 g, 7%).

Provenance & Evidence