Reaction Steps
A solution of (2S,3R,4S)-2-((4-methoxybenzyl)oxy)-7-methyl-4-vinyloctan-3-ol (2.0 g, 6.53 mmol) in anhydrous DMF (15 mL) was added at room temperature to a solution of NaH (0.326 g, 8.16 mmol, 60% dispersion in mineral oil) in anhydrous DMF (6.0 mL). The reaction was stirred for 15 min at room temperature, then isobutyl 4-methylbenzenesulfonate (1.66 mL, 8.16 mmol) was added at room temperature and the reaction was heated at 50° C. and stirred for 1 h. The reaction was cooled down to room temperature and NaH (0.261 g, 6.53 mmol) followed by isobutyl 4-methylbenzenesulfonate (1.33 mL, 6.53 mmol) were added and heating continued for 2 h at 50° C., after which the reaction was again cooled down to room temperature and a third batch of NaH (0.131 g, 3.27 mmol) and isobutyl 4-methylbenzenesulfonate (0.67 mL, 3.27 mmol) were added and the reaction was heated at 50° C. for 7 h. The reaction mixture was quenched with saturated NH4Cl and the phases were separated. The aqueous phase was extracted with Et2O, and the combined organic phases were washed with brine, dried over MgSO4, concentrated, and purified by column chromatography on SiO2 (gradient, hexanes/ethyl acetate) to furnish the title product as a colorless oil (2.05 g, 87%): 1H NMR (400 MHz, CDCl3) δ 7.29-7.21 (m, 2H), 6.90-6.83 (m, 2H), 5.61-5.49 (m, 1H), 5.04-4.89 (m, 2H), 4.53-4.33 (m, 2H), 3.80 (s, 3H), 3.64-3.51 (m, 2H), 3.28-3.16 (m, 2H), 2.15-2.02 (m, 1H), 1.90-1.77 (m, 1H), 1.76-1.60 (m, 1H), 1.54-1.41 (m, 1H), 1.28-1.11 (m, 2H), 1.17 (d, J=6.3 Hz, 3H), 1.08-0.96 (m, 1H), 0.95-0.88 (m, 6H), 0.86 (d, J=6.4 Hz, 3H), 0.85 (d, J=6.4 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 158.97, 140.43, 131.09, 129.06, 115.66, 113.67, 84.26, 79.58, 76.41, 70.05, 55.26, 47.38, 36.46, 29.13, 28.21, 27.85, 22.91, 22.47, 19.66, 19.55, 14.25; ESIMS m/z 385.4 ([M+Na]+).
