To a solution of 14 (956 mg, 1.1 mmol) in 95% ethanol (25 mL) and EtOAc (25 mL) was added 10% Pd/C (130 mg). The resulting mixture was stirred at room temperature overnight under H2 (1 atm). The catalyst was then removed by filtration and, after evaporation to dryness, the crude product was purified by flash column chromatography, eluting with 40% EtOAc in hexane (with 0.1% Et3N) to yield 671 mg (78%) of 15 as a light yellow oil. Rf=0.3 (in 40% EtOAc/hexane); 1H NMR (300 MHz, CDCl3) δ 8.1 (s, 1H), 7.18 (d, 1H, J=8.0 Hz), 6.95 (d, 2H, J=7.2 Hz), 6.69 (m, 3H), 6.57 (m, 1H), 5.28 (s, 4H), 4.94 (s, 1H), 3.85 (m, 4H), 3.69 (s, 4H), 3.57 (m, 4H), 3.38 (s, 6H), 1.41 (s, 18H); 13C NMR (75 MHz, CDCl3) δ 171.2, 153.8, 150.6, 147.4, 146.5, 144.8, 144.4, 144.2, 136.3, 126.3, 119.6, 116.7, 116.6, 116.1, 115.8, 115.5, 105.9, 94.6, 81.9, 71.4, 68.0, 59.0, 56.9, 43.1, 27.9; 19F NMR (282 MHz, CDCl3) δ −140.4 (dd, 2 F); mass spectrum, calculated for C46H55F2NO13 (M−17) 761.3, Found 761.7.
