At −80° C. oxalylchloride (36 mg, 0.28 mmol) was dissolved in dry CH2Cl2, while DMSO (50 ul, 0.6 mmol) were added slowly. The solution was stirred under Ar. For 15′. 351a (100 mg, 0.25 mmol) was dissolved in 2 ml CH2Cl2, and this solution was added dropwise to the above reaction mixture at −80° C. The reaction was stirred for 15′ at low temperature, before DIEA (0.21 ml, 1.25 mmol) was added. The reaction was stirred at −80° C. for 30′ and allowed to warm to it during 2 h. A white solid was formed, the reaction was quenched with water and extracted with CH2Cl2 several times. The combined organic layers were dried over MgSO4 and evaporated to dryness. The crude was purified by flash chromatography on silica gel using EtOAc/cyclohexane 2:1 as eluent. 351b (80 mg, 80%) was obtained as a colourless solid.: H′ NMR (CDCl3) δ 7.72 (d, J=8.7 Hz, 2H), 7.46 (d, J=3.8 Hz, 1H), 7.42 (d, J=8.7 Hz, 2H), 7.08 (d, J=3.8 Hz, 1H), 6.59 (t, J=5.8, 1H), 4.80 (d, J=6.0 Hz, 2H), 3.58 (t, J=7.5 Hz, 2H), 3.50 (s, 3H), 2.54 (t, J=7.5, 2H), 3.35-3.23 (m, 3H), 2.95 (m, 2H), 1.94 (m, 2H), 1.86 (m, 2H), 1.70-1.50 (m, 5H), 130-1.20 (m, 8H), 0.87 (t, J=6.8, 3H), M/Z APCI-399.0 (M+1), 397.2 (M−1)
