Br[C:2]1[CH:3]=[N:4][CH:5]=[C:6]([CH:9]=1)[CH:7]=[O:8].[C:10]([C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)#[CH:11].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C(N(CC)CC)C.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.[Cu]I>[C:12]1([C:10]#[C:11][C:2]2[CH:3]=[N:4][CH:5]=[C:6]([CH:9]=2)[CH:7]=[O:8])[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1A solution of 5-bromonicotinaldehyde (15 g, 81 mmol) and ethynylbenzene (9.74 mL, 89 mmol) in triethylamine (150 mL) was purged with nitrogen for 30 min. The reaction was treated with triphenylphosphine (0.656 g, 2.50 mmol), and purged 10 minutes longer. To this was added bis(triphenylphosphine)palladium dichloride (0.147 g, 0.210 mmol) and copper(I) iodide (0.032 g, 0.169 mmol). After purging 10 min longer, the reaction was warmed to a gentle reflux. The reaction was heated at reflux for 24 h. The reaction was cooled to room temperature, diluted with ethyl acetate, poured into water, and the layers were separated. The organics were washed again with water, then brine, dried over magnesium sulfate, and concentrated. Column chromatography (20% EtOAc/Hex) gave 16.05 g (96%) as faint yellow crystalline solid. 1H NMR (CDCl3) δ: 10.16 (s, 1H), 9.01 (dd, J=17.1, 1.8 Hz, 2H), 8.30 (t, J=2.0 Hz, 1H), 7.54-7.66 (m, 2H), 7.38-7.47 (m, 3H). 13C NMR (CDCl3) δ: 190.2, 156.8, 150.3, 138.2, 131.9, 130.9, 129.4, 128.7, 122.0, 121.5, 94.5, 84.7. Mass spec.: 208.0 (MH)+.
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