(S)-tert-Butyl 2-(5-iodo-1H-imidazol-2-yl)pyrrolidine-1-carboxylate (750 mg, 2.07 mmol) and copper(I) iodide (79 mg, 0.41 mmol) were dissolved into DMF (20 mL) and triethylamine (1.439 mL, 10.33 mmol). The reaction solution was vacuum flushed for 10 minutes (aspirator vacuum, flushed with nitrogen) and then ethynyltrimethylsilane (1.2 mL, 8.3 mmol) and finally Pd(PPh3)4 (119 mg, 0.103 mmol) were added. The flask was flushed with nitrogen, seal and heated at 50° C. overnight. The reaction was concentrated to a crude black tar, dissolved into DCM and purified via BIOTAGE® Horizon (80 g SiO2, 20-40% EtOAc/hexanes) to yield (S)-tert-butyl 2-(5-((trimethylsilyl)ethynyl)-1H-imidazol-2-yl)pyrrolidine-1-carboxylate (546 mg, 1.64 mmol, 79% yield) as a yellow solid. This material was used without further purification. LC-MS retention time 1.393 min; m/z 332.33 (MH−). LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a PHENOMENEX® Luna 10u C18 3.0×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 5 mL/min, a gradient of 100% Solvent A/0% Solvent B to 0% Solvent A/100% Solvent B, a gradient time of 2 min, a hold time of 1 min, and an analysis time of 3 min where Solvent A was 5% acetonitrile/95% H2O/10 mM ammonium acetate and Solvent B was 5% H2O/95% acetonitrile/10 mM ammonium acetate. MS data was determined using a MICROMASS® Platform for LC in electrospray mode. 1H NMR (400 MHz, CDCl3) δ ppm 7.19-7.13 (m, 1H), 4.92-4.85 (m, 1H), 3.43-3.31 (m, 2H), 3.04-2.83 (m, 1H), 2.20-1.88 (m, 3H), 1.51 (s, 3H), 1.49 (s, 6H), 0.25 (s, 3H), 0.23 (s, 6H).
