Dichloromethane → Ethyl 5-(2-trimethylsilyl-ethyn-1-yl)-thiophene-2-carboxylate

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Reaction Steps

Under an argon atmosphere a solution of 32.5 g (138.0 mmol) ethyl 5-bromo-thiophene-2-carboxylate in 320 ml acetonitrile and 640 ml THF is combined with 1.3 g (7.0 mmol) copper-(I)-iodide and 39.0 g (276.0 mmol) trimethyl-silylacetylene with stirring, the mixture is stirred for 5 min and then 5.6 g (7.0 mmol) 1,1-bis-(diphenylphosphino)-ferrocene-dichloropalladium(II))-PdCl2 in a complex with CH2Cl2 1/1 and 57.4 ml (414.0 mmol) TEA are added. The reaction mixture is stirred overnight at room temperature, evaporated down i. vac., the residue is combined with ethyl acetate and washed with ammonia solution (5%) and water. The organic phase is dried on sodium sulphate and evaporated to dryness i. vac. The residue is combined with diethyl ether, the precipitate is suction filtered and dried.

Provenance & Evidence