2-(2-Methoxyphenyl)thiophene → Methyl 5-(2-methoxyphenyl)thiophene-2-carboxylate

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Reaction Steps

2-Thienyl-1-methoxybenzene (10 g, 53 mmol) is cooled to −78° C. in dry tetrahydrofuran (265 ml) under nitrogen while stirring. n-Butyl lithium in hexanes (1.6M, 37 ml, 59 mmol, 1.1 eq.) is added slowly and the resulting mixture is stirred cold for an hour. Chloromethyl formate (4.1 ml, 53 mmol, 1.0 equivalent) is added and the reaction is stirred cold for another hour. The mixture is allowed to warm to room temperature before quenching with saturated bicarbonate solution and ethyl acetate. The layers are separated and the organic phase is washed with brine, dried over sodium sulfate and concentrated. The residue is purified via flash chromatography in 5% ethyl acetate/hexanes to afford 7.9 g of 2-(5-methoxycarbonylthien-2-yl)-1-methoxybenzene (61%).

Provenance & Evidence