Bromide ion → HCID 10778347, compound

Participants

Reaction Steps

To a solution of 4-bromo-[1,2]naphthoquinone (350 mg, 1.48 mmol) in THF (20 mL) and H2O (5 mL) was added 2-chlorophenylboronic acid (231 mg. 1.48 mmol). followed by tri-o-tolylphosphine (45 mg, 148 μmol) and K2CO3 (614 mg, 4.44 mmol). The mixture was deoxygenated with bubbling N2 for about ten minutes, at which time the N3 line was removed and tris(dibenzylideneacetone)dipalladium(0) (68 mg, 74 μmol) was added. The resultant mixture was heated to reflux for 2 hours under N2, at which point no starting bromide was detectable by TLC (hexanes:ethyl acetate, 1:1, v/v). The mixture was cooled to room temperature and the THF evaporated under reduced pressure. The dried material was dissolved in ethyl acetate, washed sequentially with saturated aqueous ammonium chloride, H2O and brine, dried over Na2SO4, filtered, and evaporated under reduced pressure. The isolated material was chromatographed on silica gel (hexanes-ethyl acetate, 4:1, v/v) and dried to yield the product, 4-(2-chloro-phenyl)-[1,2]naphthoquinone, as an orange solid. 1H NMR (300 MHz, CDCl3) δ 8.21 (1H, dd, J=6.9, 2.1 Hz), 7.56-7.52 (3H, m), 7.48-7.44(2H, m), 7.44 (1H, m), 6.91 (1H, dd, J=2, 6 Hz), 6.39 (1H, s); HPLC: 7.45 min.

Provenance & Evidence