Reaction Steps
An oven-dried 100 mL Schlenk flask was cooled under nitrogen and was then charged with NaH (60% dispersion in mineral oil, 1.24 g, 31.0 mmol) and anhydrous DMF (50 mL). A solution of (2S,3R,4S)-4-(2,4-difluorobenzyl)-2-((4-methoxybenzyl)oxy)hex-5-en-3-ol (8.06 g, 22.2 mmol) in anhydrous DMF (10 mL) was added via canula over a period of 6 min followed by an anhydrous DMF rinse (5 mL) of the source flask and needle. Gas evolution was observed, and the resulting white suspension was stirred at room temperature for 90 min, at which point the reaction color had turned red. Benzyl bromide (4.23 mL, 35.6 mmol) was added and the reaction was heated to 40° C. After stirring for 3 hours, the heat source was removed and the reaction was cooled to room temperature. Saturated aqueous NH4Cl solution (20 mL) was added, and the mixture was allowed to stir for 30 min, at which point gas evolution had ceased. The crude mixture was then diluted with H2O (50 mL) and extracted with Et2O (100 mL×3). The combined organic extracts were washed with saturated aqueous NH4Cl solution (100 mL), dried over anhydrous MgSO4, filtered, concentrated, and the residue was purified by column chromatography on SiO2 (0%→10% methyl tert-butylether (MTBE)/hexane gradient) to furnish the title product as white solid (90% Pure, 8.47 g, 84%): mp 141-144° C.; 1H NMR (400 MHz, CDCl3) δ 7.41-7.30 (m, 4H), 7.30-7.24 (m, 3H), 7.05-6.96 (m, 1H), 6.90-6.84 (m, 2H), 6.76-6.67 (m, 2H), 5.57 (dddd, J=17.1, 10.3, 9.0, 1.3 Hz, 1H), 4.88 (dd, J=10.2, 1.9 Hz, 1H), 4.87 (d, J=11.4 Hz, 1H), 4.72 (ddd, J=17.2, 1.8, 0.5 Hz, 1H), 4.63 (d, J=11.4 Hz, 1H), 4.53 (d, J=11.3 Hz, 1H), 4.40 (d, J=11.3 Hz, 1H), 3.79 (s, 3H), 3.70 (qd, J=6.2, 3.8 Hz, 1H), 3.52 (dd, J=6.9, 3.9 Hz, 1H), 3.09 (d, J=10.4 Hz, 1H), 2.59-2.44 (m, 2H), 1.25 (d, J=6.3 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 161.24 (dd, J=245.7, 11.9 Hz), 161.09 (dd, J=247.0, 11.6 Hz), 159.11, 138.90, 138.24, 132.05 (dd, J=9.4, 6.7 Hz), 130.92, 129.17, 128.33, 127.97, 127.53, 123.45 (dd, J=15.9, 3.7 Hz), 116.95, 113.78, 110.59 (dd, J=20.8, 3.7 Hz), 103.33 (dd, J=26.5, 25.0 Hz), 83.67, 76.56, 74.18, 70.41, 55.28, 47.98, 29.75, 14.24; 19F NMR (376 MHz, CDCl3) δ −113.06 (d, J=6.8 Hz), −113.95 (d, J=6.4 Hz); ESIMS: m/z 475 ([M+Na]+).
