Compound 1B (310 mg, 0.92 mmol) was dissolved in 1 mL of dry acetonitrile. Tosic acid (875 mg, 4.6 mmol) was dissolved in 3 mL of dry acetonitrile. Molecular sieves were added to both solutions and stood for 30 minutes. The solution of tosic acid was then added the other mixture and the reaction was stirred at room temperature for 3 hours. After that time the reaction was filtered and the solid washed with acetonitrile and CH2Cl2). The filtrate was concentrated to afford a thick colourless oil. It was dissolved in 2 mL of ethanol. Triethylamine (640 μL, 1.48 mmol) and 2-(Methoxy-p-tolyl-methylene)-malononitrile (182 mg, 0.92 mmol) were successively added. The reaction was then heated at 60° C. for 3 hours. After cooling down, the reaction was concentrated. Water and EtOAc were then added and the aqueous phase was extracted three times with EtOAc. The combined organic layers were dried over Na2SO4 and concentrated. The oily residue obtained was purified by flash chromatography on SiO2 using 100% CH2Cl2 then CH2Cl2/MeOH 99:1. A colourless oil that solidifies slowly overnight was obtained (m=270 mg, 73%). NMR (ppm, CDCl3): δ 1.58 (s, 6H), 2.36 (s, 3H), 3.77 (d, J=6.63 Hz, 2H), 4.40 (br s, 2H), 5.08 (s, 2H), 5.59 (br t, J=5.94 Hz, 1H), 7.20 (d, J=8.55 Hz, 2H), 7.31 (m, 5H), 7.74 (d, J=8.13 Hz, 2H). 13C NMR (ppm, CDCl3): δ 21.35, 24.18, 50.56, 63.17, 66.99, 76.34, 115.22, 126.09, 128.15, 128.22, 128.33, 128.55, 129.42, 136.34, 139.11, 149.13, 151.57, 156.96. LCMS (+esi): 404.3 (M+H+).
