A suspension of Pd2(dba)3 (0.1 g, 0.113 mmol) and PtBu3 (1.38 mL, 0.455 mmol, 10% wt in hexane) in anhydrous THF (3 mL) was treated with a solution of compound 3 (0.64 g, 2.276 mmol) in THF (7 mL) followed by LiHMDS (4.55 mL, 4.552 mmol, 1 M solution in THF) at room temperature. The resulting dark brown mixture was heated to 100° C. and stirred for 3 hours in a sealed tube. The reaction mixture was cooled to room temperature and treated with 1 N HCl solution (5 mL) and stirred for 20 min. The reaction was basified with 2 N NaOH solution (25 mL) and product was extracted into CH2Cl2 (3×20 mL) and the combined organic fractions were washed with brine (20 mL) and dried (Na2SO4). The solvent was evaporated and crude product was purified by column chromatography on silica gel (2 N NH3 in MeOH:CH2Cl2, 5:95) to obtain compound 4 (0.44 g, 89%) as a syrup. 1H NMR (DMSO-d6) δ 6.38 (s, 1H), 6.30-6.23 (m, 2H), 4.31 (brs, 2H), 4.01-3.92 (m, 1H), 3.14 (t, 2H, J=8.1 Hz), 2.68 (t, 2H, J=8.1 Hz), 2.56-2.50 (m, 3H), 2.37-2.29 (m, 1H), 2.21 (s, 3H), 2.02-1.90 (m, 1H), 1.76-1.66 (m, 1H); ESI-MS (m/z, %): 218 (MH+, 100).
