3.1.5. *[(1E,6E)-4,4-bis(Methoxymethyl)-3,5-dioxohepta-1,6-diene-1,7-diyl]bis(2-methoxy-4,1-phenylene) bis[3-hydroxy-2-(hydroxymethyl)-2-methylpropanoate]* (**11**)

To a stirred solution of crude **8** (0.453 g) in DMF (1.0 mL) were added K2CO3 (0.240 g, 1.73 mmol) and MeI (0.247 g, 1.73 mmol) at 0 oC. The reaction mixture was warmed to room temperature and stirred for 6 h. Then H2O (10 mL) and diluted HCl(aq) (1 *N*, 3 mL) were added to quench the reaction. The aqueous layer was separated and extracted with EtOAc (3 × 8 mL). The combined organic extracts were washed with brine, dried over MgSO4, filtered and concentrated to give the crude product, which was then treated with HCl(aq) (6 *N*, 0.25 mL) in MeOH (2 mL) at room temperature. The reaction mixture was stirred at room temperature for 1h and then concentrated under vacuum to give the crude product, which was purified on silica gel with MeOH/CH2Cl2 (1:20) to afford **11** (73 mg) as a yellow solid (mp = 187–188 ◦C). Yield 5% for three steps; 1H-NMR (DMSO-d6) δ 7.65 (d, *J* = 16.0 Hz, 2H), 7.49 (s, 2 H), 7.31 (d, *J* = 10.0 Hz, 2H), 7.08 (d, *J* = 8.1 Hz, 2H), 6.69 (d, *J* = 16.0 Hz, 2H), 4.85 (t, *J* = 5.5 Hz, 4 H), 3.80 (s, 6H), 3.74 (s, 6 H), 3.66-3.60 (m, 8H), 1.20 (s, 6H); 13C-NMR (DMSO-d6) δ 193.1, 173.4, 167.1, 151.6, 144.4, 141.8, 133.2, 123.8, 121,9, 118.4, 112.6, 64.0, 56.3, 51.9, 51.0, 17.3; HRMS [ESI]<sup>+</sup> calculated for C35H44NaO14: 711.2629 [M + Na]+; found: 711.2633.
