C(NC(C)C)(C)C.[Li]CCCC.B.N.[Cl:15][CH2:16][CH2:17][CH2:18][C@H:19]([CH2:34][CH:35]=[CH2:36])[C:20](N([C@@H](C)[C@@H](O)C1C=CC=CC=1)C)=[O:21]>C1COCC1>[Cl:15][CH2:16][CH2:17][CH2:18][C@H:19]([CH2:34][CH:35]=[CH2:36])[CH2:20][OH:21]
A magnetically stirred solution of diisopropylamine (184 mL, 1.29 mol) in THF (600 mL) was cooled to −78° C. nBuLi (2.5M in hexane, 482 mL, 1.21 mol) was added dropwise over 35 min using an addition funnel. The cloudy mixture stirred at −78° C. for 15 min and then was warmed to 0° C. for 15 min during which time the solution became clear and light yellow. Borane-ammonia (90%, 42 g, 1.24 mol) was added in four equal portions, one minute apart. (Caution: vigorous evolution of gas). The cloudy mixture was warmed to room temperature for 20 min and then was recooled to 0° C. (R)-2-(3-chloropropyl)-N-((1S,2S)-1-hydroxy-1-phenylpropan-2-yl)-N-methylpent-4-enamide (100.2 g, 309 mmol) in THF (300 mL) was added dropwise over 10 min using an addition funnel. The reaction was warmed to room temperature and stirred for 2.5 h. The reaction was cooled to −10° C. and was quenched with HCl (3M, 1500 mL). The phases were separated and the aqueous phase was extracted with Et2O (2000 mL total). The combined organic layers were washed with 3N HCl, brine, dried over MgSO4, filtered, and concentrated under reduced pressure to furnish the crude product as a yellow oil. The crude material was purified by flash chromatography (ISCO; 330 g column; Hexane to 30% EtOAc/Hexane) to provide (R)-2-(3-chloropropyl)pent-4-en-1-ol as a clear, viscous oil (32.6 g, 200 mmol, 65%); 1H NMR (400 MHz. CDCl3) δ 5.82 (m, 1H), 5.07 (m, 2H), 3.78 (m, 1H), 3.58 (d, J=8.0 Hz, 2H), 3.54 (t, J=8 Hz, 2H), 2.14 (m, 2H), 1.85 (m, 2H), 1.64 (m, 1H), 1.49 (m, 1H).
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