Reaction Steps
An oven-dried, 100 mL round-bottomed flask was cooled under Ar and charged with 4-iodo-6-trimethylsilyldibenzofuran (5) (3.82 g, 10.4 mmol), palladium acetate (49.2 mg, 2.1 mol %), and tri-ortho-tolylphosphine (0.162 g, 5.1 mol %). The flask was fitted with a condenser and the system was alternately evacuated under high vacuum and flushed with Ar (4 cycles). Acetonitrile (16.5 mL), triethylamine (4.36 mL, 31.1 mmol), and ethyl acrylate (3.39 mL, 31.3 mmol) were added through the condenser and the mixture was heated to 85÷C in an oil bath. The reaction mixture was cooled to room temperature when the palladium precipitated after 2 hours. The mixture was concentrated under reduced pressure to give a yellow-brown solid which was then partitioned between CH2Cl2 (120 mL) and H2O (150 mL). The aqueous layer was extracted with CH2Cl2 (3×75 mL). The combined organic layers were dried over MgSO4 and concentrated under reduced pressure. The crude material was purified by flash chromatography (95:5 hexanes:ethyl acetate) to afford the pure compound (3.27 g, 93%) as an oil which solidified upon standing to afford beige solid: mp 48-52° C.; 1H NMR (d6-acetone) d 8.16 (d, Jo=7.6, 2H, Ar H1 and H9), 7.98 (d, J=16.2, 1H, --CHCHCO2Et), 7.77 (dd, Jo=7.0, Jp=0.6, 1H, Ar H3), 7.64 (dd, Jo=7.2, Jm=1.3, 1H, Ar H7), 7.44 (td, Jo=7.6, Jm=1.6, 2H, Ar H2 and H8), 7.20 (d, J=16.2, 1H, --CHCHCO2Et), 4.28 (q, J=7.1, 2H, --CO2CH2CH3), 1.34 (t, J=7.1, 3H, --CO2CH2CH3), 0.52 (s, 8H, --Si(CH3)3); 13C NMR (d6-acetone) d 167.51, 139.99, 134.60, 134.32, 129.78, 126.14, 124.59, 124.55, 124.08, 123.89, 123.36, 123.25, 122.98, 120.74, 61.27, 14.99, -0.56; EIMS m/z 338.1349, M+ calcd for C20H22O3Si 338.1338.
