Synthesis
1. BuLi (2.6 M hexane solution, 194 mL, 504 mmol) was slowly added dropwise to a stirred solution of 1-butyne (28.0 g, 518 mmol) in Et2O (500 mL) at -78 °C over 30 min. After 1 hour of reaction, chlorotrimethylsilane (64.0 mL, 504 mmol) was added dropwise over 10 minutes to the resulting lithium acetylene solution. After continuing the reaction for 10 minutes, the reaction mixture was slowly warmed to room temperature and stirred for 12 hours. Upon completion of the reaction, the reaction was quenched with water and extracted with Et2O. The organic layers were combined, washed with brine, dried over Na2SO4 and concentrated under reduced pressure. The residue was purified by distillation at atmospheric pressure to give 1-trimethylsilyl-1-butyne (47.6 g, 377 mmol, 75% yield). The boiling point of the product 1-trimethylsilyl-1-butyne [62108-37-6] was 110-113 °C. 1H NMR (CDCl3) δ 0.15 (s, 9H), 1.15 (t, J = 7.6 Hz, 3H), 2.24 (q, J = 7.6 Hz, 2H).
2. Cyclohexene (44.6 mL, 440 mmol) was slowly added to a stirred solution of BH3-SMe2 (20.9 mL, 220 mmol) in THF (400 mL) at 0 °C. After 3 hours of reaction, 1-trimethylsilyl-1-butyne (27.6 g, 219 mmol) was added over 10 minutes. The reaction was continued for 15 minutes and then the reaction mixture was slowly warmed to room temperature and stirred for 90 minutes. Upon completion of the reaction, the solvent was evaporated and the residue was diluted with pentane (100 mL) and cooled to 0 °C. To this solution, AcOH (12.6 mL, 220 mmol) was added and after stirring for 90 min, a mixture of 1-trimethylsilyl-1-butyne and pentane was obtained by reduced pressure distillation (30 °C, 13 Torr). Further purification by atmospheric pressure distillation afforded 1-trimethylsilyl-1-butyne (20.6 g, 161 mmol, 73% yield) with a boiling point of 110-115 °C. IR (pure) 2965, 1608, 1249, 838 cm-1 ; 1H NMR (CDCl3) δ 0.12 (s, 9H), 0.99 (t, J = 7.5 Hz, 3H), and 2.14 (quint-d, J = 7.5, 1.0 Hz, 2H), 5.45 (dt, J = 14.0, 1.0 Hz, 1H), 6.30 (dt, J = 14.0, 7.4 Hz, 1H); 13C NMR (CDCl3) δ 0.2, 14.2, 26.8, 128.2, 150.7.
References
[1] Tetrahedron Letters, 2015, vol. 56, # 5, p. 713 - 716
[2] Synthesis (Germany), 2016, vol. 48, # 4, p. 520 - 534
[3] Journal of the Chemical Society - Perkin Transactions 1, 1998, # 17, p. 2749 - 2763
[4] Journal of the American Chemical Society, 1980, vol. 102, # 15, p. 5012 - 5015
[5] Journal of the American Chemical Society, 1986, vol. 108, # 6, p. 1359 - 1360
