[Li]CCCC.Br[C:7](Br)=[CH:8][CH:9]([CH2:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH3:23])[CH2:10][CH2:11][CH2:12][CH2:13][CH2:14][CH3:15].O>O1CCCC1>[C:8]([CH:9]([CH2:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH3:23])[CH2:10][CH2:11][CH2:12][CH2:13][CH2:14][CH3:15])#[CH:7]n-BuLi (2.5 M in hexanes, 261 cm3, 652 mmol) is added dropwise over 60 minutes to a solution of 7-(2,2-dibromo-vinyl)-pentadecane (4.1) (117 g, 296 mmol) in anhydrous tetrahydrofuran (1350 cm3) at −78° C. The mixture is stirred for 45 minutes at −78° C. and water (1.3 L) is carefully added. The reaction mixture exotherms to −10° C. and is allowed to warm to 23° C. whilst stirring over 18 hours. The organic phase is separated, washed with brine (1500 cm3), dried over sodium sulfate, filtered and concentrated in vacuo. The crude oil is passed through a plug of silica eluting with petroleum ether (40-60° C.). The pale yellow oil is further purified by distillation under vacuum (96° C. at 0.85 mmHg) to give the title product as a colourless oil (57.7 g, Yield: 82%). NMR (1H, 300 MHz, CDCl3): δ 2.30 (m, 1H); 2.03 (d, J=2.4 Hz, 1H); 1.44 (m, 8H); 1.27 (m, 16H); 0.88 (m, 6H).
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