[Li]CCCC.[CH3:6][O:7][C:8]1[CH:12]=[CH:11][S:10][CH:9]=1.Cl[Si:14]([CH3:17])([CH3:16])[CH3:15]>CCOCC>[CH3:15][Si:14]([CH3:17])([CH3:16])[C:9]1[S:10][CH:11]=[CH:12][C:8]=1[O:7][CH3:6]A solution of n-BuLi (19.7 mL of 1.6 M in hexanes, 31.5 mmol) is added dropwise to a solution of 3-methoxythiophene (3.0 g, 26.3 mmol) in anhydrous Et2O (20 mL) under nitrogen at −70° C. The mixture is stirred at −70° C. for 2 hr. Chlorotrimethylsilane (4.5 mL, 35.4 mmol) is added slowly to the solution. The mixture is warmed to room temperature and stirred for 3 hr. The reaction is quenched with water (50 mL) and hexanes (100 mL). The aqueous layer is extracted with hexanes (50 mL). The combined organic extracts are dried (Na2SO4), filtered and concentrated. The crude product is chromatographed on silica gel, eluting with hexanes to afford the title compound (4.0 g, 82%) as a colorless liquid.
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