Synthesis
We optimized the synthesis steps. Deionized water (200 mL) and 4-[(trimethylsilyl)ethynyl]aniline (8.4 g, 44 mmol) were added to a 500 mL round-bottomed flask and stirred for 15 min at room temperature. Subsequently, concentrated hydrochloric acid (20.5 mL, 12 M) was slowly added to the reaction system and stirring was continued for 10 minutes. The reaction system was cooled to 0 °C and an aqueous solution of sodium nitrite (NaNO2, 3.96 g, 57 mmol) was added slowly and dropwise. The reaction system was kept stirred in an ice bath for 30 min. After that, the ice bath was removed and replaced by a room temperature water bath and stirring was continued for 30 min. After completion of the reaction, the aqueous phase was extracted with dichloromethane (3 x 100 mL). The organic phases were combined and transferred to another 1 L round-bottomed flask and placed in an ice bath and stirred for 10 min. An aqueous solution of potassium iodide (KI, 11.4 g, 69 mmol) was slowly added dropwise at 0 °C. The reaction mixture was allowed to warm up naturally to room temperature and stirring was continued for 6 hours. At the end of the reaction, the aqueous layer was extracted with ether. The organic layers were combined, washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure to give the crude product. The crude product was purified by alumina column chromatography using petroleum ether as eluent to afford the target compound (4-iodophenylethynyl)trimethylsilane (11.3 g, 85% yield) as a white solid.IR (KBr, cm-1) ν: 2918, 2725, 2161, 1600, 1463, 1365, 1125, 1169, 951, 842, 750 , 723, 556, 471; 1H NMR (300 MHz, CDCl3, ppm) δ: 0.24 (s, 9H), 7.18 (d, J = 9.0 Hz, 2H), 7.63 (d, J = 9.0 Hz, 2H); 13C NMR (75 MHz, CDCl3, ppm) δ: -0.6, 93.9, 95.4, 103.5, 122.2, 132.9, 136.9.
References
[1] Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, 2014, vol. 133, p. 229 - 240
[2] Journal of the American Chemical Society, 2001, vol. 123, # 34, p. 8177 - 8188
[3] Journal of Organic Chemistry, 2003, vol. 68, # 6, p. 2167 - 2174
[4] Tetrahedron, 1996, vol. 52, # 15, p. 5495 - 5504
[5] Tetrahedron, 2002, vol. 58, # 52, p. 10387 - 10405
