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Typical Procedure for the Preparation of 6a: Bisbenzonitriledichloropalladium (75 mg, 0.20 mmol) and copper iodide (25 mg, 0.10 mmol) were added to a dry round bottomed flask which was purged with argon and filled with dry THF (10 mL). Tri-2-furylphoshine (94 mg, 0.40 mmol) and triethylamine (1.1 mL, 7.80 mmol) were added, followed by 3,5-dibromobenzoic acid ethyl ester (1.01 g, 3.30 mmol). The reaction was stirred at r.t. for 20 min. Propargyl alcohol (0.55 g, 9.80 mmol) was added gradually over 20 min, and the reaction was refluxed under argon for 10 h. The residue of palladium salts was filtered and washed with THF. The combined filtrate and washings were evaporated under reduced pressure. The residue was taken up in chloroform (50 mL) and washed with 1 M hydrochloric acid (20 mL) followed by brine (2 × 20 mL). The combined organic layers were dried over sodium sulfate, filtered at the pump and concentrated in vacuo to yield a brown oil. Subsequent purification using column chromatography (SiO2, 6:4 CH2Cl2:EtOAc) afforded a white solid (mp 163-164 °C, 0.351 g, 42%).
1H NMR (250 MHz, CDCl3): δ = 1.17 (t, 3 H, J = 7.1 Hz, CH3), 4.22 (q, 2 H, J = 7.1 Hz, CH2), 4.42 (s, 4 H, 2 × CH2), 7.43 (t, 1 H, J = 1.6 Hz, ArH), 7.86 (d, 2 H, J = 1.6 Hz, ArH). 13C NMR (67.5 MHz, CDCl3): δ = 13.2 (CH3), 50.2 (2 CH2), 60.6 (CH2), 82.5 (2 × C≡C), 88.1 (2 × C≡C), 122.3 (2 × ArCH), 129.7 (ArCH), 131.3 (2 × ArC-C), 137.3 (ArC-COOEt), 164.4 (C=O); IR: νmax 666, 723, 1414, 1462, 1585, 1735, 2354, 2856, 2923 cm-1; m/z (TOF MS ES+) mobile phase 70:30 CH3CN:0.05 M NH4OAc(aq), flow injection: calculated for C15H14O4 258.2732, found 792.3010 [3 M + NH4]+, 534.2120 [2 M + NH4]+, 517.1837 [2 M + H]+, 481.1641 [2 M + H - 2 H2O]+, 300.1233 [MH + CH3CN]+, 259.0965 [MH+].
17
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