C([Li])CCC.[C:6](#[N:8])[CH3:7].[CH2:9]([CH:11]([CH2:17][CH3:18])[C:12](OCC)=[O:13])[CH3:10].Cl>C1COCC1>[CH2:9]([CH:11]([CH2:17][CH3:18])[C:12](=[O:13])[CH2:7][C:6]#[N:8])[CH3:10]To a solution of n-butyllithium (56.6 ml, 1.6M solution in hexane, 90.6 mmol) in THF (60 ml) was added a solution of acetonitrile (3.71 g, 4.73 ml, 90.5 mmol) in THF (12 ml) slowly at a temperature between −78° C. and −70° C. Then a solution of ethyl 2-ethylbutanoate (6.52 g, 7.5 ml, 45.2 mmol) in THF (17 ml) was added and the reaction mixture was stirred for 1 h at −78° C. and for 1.5 h at −45° C. Then cold 2M HCl was added carefully to adjust the pH to 7. The mixture was extracted with DCM and the combined extracts were dried with MgSO4 and evaporated. The crude material was purified by chromatography (silica gel, heptane/EtOAc 9:1) to afford the title compound (6.29 g, 100%) as light yellow oil. MS (ESI): 138.3 (M−H)−.
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