1-Ethynyladamantane

Synthesis

The general procedure for the synthesis of 1-alkynyladamantanes from the compound (CAS: 91800-98-5) is as follows: potassium tert-butoxide (4.2 g, 37.9 mmol) was added to a Schlenk flask in an argon-protected glove box. Using the anhydrous handling technique, freshly distilled tetrahydrofuran (THF, 20 mL) was added to the flask and the mixture was cooled to -10 °C. Subsequently, compound (8) (4.1 g, 12.6 mmol) was added dropwise and the reaction mixture was stirred at room temperature. The reaction was kept under argon atmosphere for 4 days. After completion of the reaction, the reaction was quenched with water and extracted twice with diethyl ether (20 mL). The organic layers were combined, washed sequentially with water and brine, and then dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated to dryness under vacuum and the residue was purified by silica gel column chromatography using hexane as eluent. The eluate was concentrated to give a white solid product (1.8 g, 91% yield). The structure of the product was confirmed by the following characterization data: 1H NMR (500 MHz, CDCl3) δ 2.08 (1H, s, ≡CH), 1.94 (3H, m, adamantane-H), 1.87 (6H, m, adamantane-H2), 1.67 (6H, m, adamantane-H2); 13C NMR (125.8 MHz, CDCl3) δ 93.1 (≡C-), 66.6 (≡CH), 42.7, 36.3, 29.4, 27.9 (adamantane-C); mass spectrometry (GC-EI, positive ion mode) m/z calculated value of 160.1252 (M+), measured value of 160.0990.

References

[1] Journal of Medicinal Chemistry, 2012, vol. 55, # 16, p. 7290 - 7294,5
[2] Patent: WO2013/82150, 2013, A1. Location in patent: Paragraph 0124
[3] Patent: US2015/322093, 2015, A1. Location in patent: Paragraph 0177
[4] Tetrahedron, 1989, vol. 45, # 10, p. 2925 - 2936
[5] Chemische Berichte, 1962, vol. 95, p. 1039 - 1042