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

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Reaction Steps

A solution of methyl 4-(4-bromo-1-methyl-1H-pyrazol-5-yl)-5-methyl-2-thiophenecarboxylate (200 mg, 0.64 mmol) [prepared in Example 99], potassium carbonate (438 mg, 3.17 mmol), bis(tri-t-butylphosphine)palladium(0) (324 mg, 0.64 mmol) and 2,4,6-trivinylcycloboroxane-pyridine complex (77 mg, 0.32 mmol) in 1,4-dioxane (5.3 ml) and H2O (1 ml) was stirred at 80° C. in a sealed tube for 12 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-methyl-2-thiophenecarboxylate (135 mg, 0.515 mmol, 81% yield) as a yellow oil: LCMS (ES) m/z=250 (M+H)+.

Provenance & Evidence