Hydrochloric Acid → 5-(2-(Tert-butyldimethylsilyloxy)ethyl)-2-chlorothiophene-3-carbaldehyde

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Reaction Steps

tert-Butyl(2-(5-chlorothiophen-2-yl)ethoxy)dimethylsilane [Aromatic Intermediate 17, step a] (0.8 g) was added dropwise over 5 min to a stirred solution of butyllithium (2.5M in hexanes, 1.73 mL) and 2,2,6,6-tetramethylpiperidine (0.73 mL) in THF (25 mL) at −78° C. The resulting mixture was stirred for 2 h then DMF (0.67 mL) was added. The mixture was stirred for a further 1 h and allowed to warm to RT. The reaction mixture was cautiously poured into aqueous HCl (0.5M, 200 mL) and extracted with ethyl acetate (3×100 mL). The combined organic phases were washed with water (2×100 mL) and brine (100 mL), then dried over sodium sulphate, filtered and evaporated. The resulting oil was purified by silica gel chromatography eluting with isohexane to 5% ether in isohexane gradient. The fractions containing product were combined and evaporated to give the subtitled compound as a clear oil. Yield 0.80 g.

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