C(=O)([O-])[O-].[K+].[K+].[Br:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1B(O)O.Br[C:18]1[CH:23]=[C:22]([O:24][CH3:25])[CH:21]=[C:20]([O:26][CH3:27])[CH:19]=1.N#N.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C([O-])(=O)C.[Pd+2].C([O-])(=O)C.COCCOC.O>[Br:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[C:18]1[CH:23]=[C:22]([O:24][CH3:25])[CH:21]=[C:20]([O:26][CH3:27])[CH:19]=1To a 250-mL round bottom flask equipped with a magnetic stir bar was added water (41 mL) and 1,2-dimethoxyethane (41 mL). The solution was sparged with nitrogen for 20 minutes, and then potassium carbonate (11.1 g, 81.0 mmol, 3 equiv), 2-bromophenylboronic acid (6.35 g, 31.6 mmol, 0.98 equiv) and 1-bromo-3,5-dimethoxybenzene (7.00 g, 32.2 mmol, 1 equiv) were added. The flask was purged with N2 for 10 minutes before finally adding palladium(II) acetate (145 mg, 0.645 mmol, 0.02 equiv) and triphenylphosphine (677 mg, 2.58 mmol, 0.08 equiv). The reaction mixture was heated to 85° C. under a positive pressure of nitrogen for 16 hours. After cooling to room temperature, the phases were partitioned. The organic phase was collected and the aqueous phase was washed with ethyl acetate (3×20 mL). The combined organic fractions were washed with brine (50 mL), dried over sodium sulfate, filtered, and concentrated on a rotary evaporator. The crude yellow oil was purified by column chromatography on the Isco (120-g column; gradient: 2 column volumes heptane, ramp up to 94:6 heptane:ethyl acetate over 8 column volumes, hold at 94:6 for 6 column volumes) to afford the title compound as a colorless oil (4.51 g, 94 area % by HPLC, 48% yield). 1H NMR (400 MHz, CDCl3) δ ppm 7.68-7.62 (m, 1H), 7.40-7.31 (m, 2H), 7.24-7.15 (m, 1H), 6.55 (d, J=2.3 Hz, 2H), 6.50 (t, J=2.3 Hz, 1H), 3.83 (s, 6H). 13C NMR (100 MHz, CDCl3) δ ppm 159.8, 142.6, 142.1, 132.8, 130.7, 128.5, 127.0, 122.1, 107.4, 99.6, 55.5.
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