A solution of 10b (2.0 g, 6.4 mmol), pentachlorophenol (1.9 g, 7.0 mmol), DCC (1.6 g, 7.7 mmol) and DMAP (0.08 g, 0.64 mmol) in 100 mL of EtOAc was stirred at room temperature for 24 h. The mixture was filtered through celite and the solvent removed in vacuo. The crude product was purified by silica gel chromatography eluting with 25% EtOac-hexanes to give 2.6 g (72%) of 11b1 as white solid. 1H NMR (CDCl3, 300 MHz) δ 1.26-1.32 (m, 6H), 2.54 (d, J=1.2 Hz, 3H), 4.12-4.21 (m, 4H), 6.34 (d, J=1.2 Hz, 1H), 7.2 (d, J=8.7 Hz, 2H), 7.49 (d, J=8.7 Hz, 2H). 11C NMR (CDCl3, 75.0 MHz) δ 16.0, 16.1, 18.4, 64.8, 64.8, 68.9, 113.4, 120.2, 120.3, 128.0, 128.1, 131.2, 131.9, 137.8, 141.9, 144.3, 152.1, 160.6, 161.9. HRMS (M+H) calc, 560.9362; found, 560.9197.
