Reaction Steps
A 0.5 M solution of 9-borabicyclo[3.3.1]nonane in anhydrous THF (7.0 mL, 3.50 mmol) was added to a solution of 1-((2S,3R,4S)-3-(cyclopropylmethoxy)-4-((4-methoxybenzyl)oxy)-2-vinylpentyl)-4-fluorobenzene (960 milligrams (mg), 2.409 mmol) in anhydrous THF (5 mL) at 0° C. The resulting solution was warmed to room temperature and stirred for 1 h, then heated to 50° C. for 2 h. The reaction was cooled to room temperature, a solution of K3PO4 (3 M aqueous, 1.61 mL, 4.82 mmol) was added, and the reaction was stirred for 15 min at room temperature. To the mixture was added a solution of (Z)-benzyl 3-bromo-2-((tert-butoxycarbonyl)amino)acrylate (870 mg, 2.44 mmol), prepared using a similar procedure to that disclosed in Singh, J. et al. Org. Lett. 2003, 5, 3155-3158, in degassed DMF (2 mL) and PdCl2(dppf) (88.0 mg, 0.120 mmol). The reaction was heated overnight at 60° C., cooled, diluted with Et2O, and washed with saturated aqueous NaHCO3. The phases were separated and the aqueous phase was extracted with Et2O. The combined organic phases were washed with saturated aqueous NH4Cl and water, dried over MgSO4, concentrated, and purified by column chromatography on SiO2 (gradient, hexanes/ethyl acetate) to furnish the title product as a pale yellow oil (1.43 g, 88%): 1H NMR (400 MHz, CDCl3) δ 7.38-7.26 (m, 5H), 7.26-7.19 (m, 2H), 6.97-6.89 (m, 2H), 6.88-6.78 (m, 4H), 6.39 (t, J=7.2 Hz, 1H), 6.29 (s, 1H), 5.24-5.10 (m, 2H), 4.61-4.25 (m, 2H), 3.73 (s, 3H), 3.64-3.53 (m, 1H), 3.45-3.31 (m, 2H), 3.22 (dd, J=7.2, 2.8 Hz, 1H), 2.79 (dd, J=14.0, 4.8 Hz, 1H), 2.37 (dd, J=14.0, 9.5 Hz, 1H), 2.25-2.08 (m, 2H), 1.92-1.79 (m, 1H), 1.57-1.43 (m, 1H), 1.43 (s, 9H), 1.39-1.28 (m, 1H), 1.28 (d, J=6.0 Hz, 3H), 1.09-0.96 (m, 1H), 0.53-0.44 (m, 2H), 0.21-0.13 (m, 2H); 13C NMR (101 MHz, CDCl3) δ 164.48, 160.91 (d, J=243.2 Hz), 158.99, 153.40, 136.94 (d, J=3.2 Hz), 136.82, 135.55, 130.26, 130.24 (d, J=7.7 Hz), 129.39, 128.31, 128.04, 128.00, 126.23, 114.62 (d, J=20.9 Hz), 113.58, 82.58, 80.01, 76.69, 74.41, 69.70, 66.72, 54.94, 40.81, 34.83, 28.49, 27.99, 25.75, 16.00, 11.01, 2.86, 2.78; 19F NMR (376 MHz, CDCl3) δ −117.70; ESIMS m/z 676.4 ([M+H]+).
