Potassium Carbonate → methyl 4-(4-ethenyl-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate

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Reaction Steps

A solution of methyl 4-(4-bromo-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate (300 mg, 0.91 mmol), potassium carbonate (630 mg, 4.56 mmol), bis(tri-t-butylphosphine)palladium(0) (23 mg, 0.05 mmol) and 2,4,6-trivinylcycloboroxane-pyridine complex (110 mg, 0.46 mmol) in 1,4-dioxane (5 ml) and water (1 ml) was stirred at 80° C. in a sealed tube for 2 h. The reaction contents were partitioned between H2O-DCM and the aqueous phase was washed several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated and purified via column chromatography (10-50% EtOAc in hexanes) affording methyl 4-(4-ethenyl-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate (187 mg, 0.66 mmol, 73% yield) as a clear oil: LCMS (ES) m/z=277 (M+H)+.

Provenance & Evidence