3.1.7. *2,2-bis[(E)-3-(3,4-Dimethoxyphenyl)acryloyl]propane-1,3-diylbis[3-hydroxy-2-(hydroxymethyl)-2 methylpropanoate]* (**14**)

To a solution of **12** (0.170 g, 0.37 mmol) in CH2Cl2 (4 mL) was added NEt3 (0.15 mL, 1.10 mmol), DMAP (0.110 g, 0.92 mmol) and 2,2,5-trimethyl-1,3-dioxane-5-carbonyl chloride **13** (0.210 g, 1.10 mmol) sequentially at room temperature. The reaction mixture was stirred at the same temperature for 12h and then concentrated under vacuum to give the crude product, which without purification was treated with HCl(aq) (6 *N*, 0.1 mL) in MeOH (0.5 mL). The resulting mixture was stirred at room temperature for 1h and then concentrated under vacuum to give the crude product, which was purified by flash chromatography on silica gel with MeOH/CH2Cl2 (1:19) to afford compound **14** (16 mg, 7% for two steps) as a yellow solid; mp > 300 ◦C; 1H-NMR (DMSO-d6) δ 7.64 (d, *J* = 15.5 Hz, 2H), 7.34–7.30 (m, 4H), 7.03 (d, *J* = 15.0 Hz, 2H), 6.99 (d, *J* = 8.0 Hz, 2H), 4.74 (s, 4H), 4.63 (t, *J* = 5.5 Hz, 4H), 3.79 (s, 12H), 3.40-3.37 (m, 8H), 0.95(s, 6H); 13C-NMR (DMSO-d6) δ 193.3, 174.6, 152.1, 149.4, 145.0, 127.1, 124.7, 119,5, 112.0, 111.4, 66.9, 63.9, 62.3, 56.1, 56.1, 50.7, 17.0; HRMS [ESI]<sup>+</sup> calculated for C35H44NaO14: 711.2629 [M + Na]+; found: 711.2620.
