N,N,N',N'-Tetramethylethylenediamine → tert-Butyl 5-formylthiophene-2-carboxylate

Participants

Reaction Steps

A solution of t-butyl 2-thiophenecarboxylate (1.84 g, 10 mmol) and N,N,N',N'-tetramethylethylenediamine (1.74 g, 15 mmol) in anhydrous tatrahydrofuran was stirred in a nitrogen stream under cooling with dry ice/acetone, followed by the dropwise addition of a 1.7M solution (8.0 ml) of t-butyllithium (13.6 mmol) in pentane. The obtained mixture was stirred as such for about 50 minutes. Anhydrous dimethylformamide (15 ml) was gradually dropped into the resulting mixture to conduct a reaction. The dry ice/acetone was removed to raise the temperature of the mixture to room one. The resulting mixture was stirred for 40 minutes and poured into 300 ml of a diethyl ether/0.3N HCl (3:1) mixture. The obtained mixture was stirred for a while. The organic layer was recovered, washed with a phosphate buffer solution having a pH of 7 and an aqueous solution of common salt, dehydrated and distilled to remove the solvent. The residue was purified by silica gel column chromatography (developer: n-hexane/ethyl acetate=8:1) to give t-butyl 5-formyl-2-thiophenecarboxylate. yield: 1.7 g

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