A solution of 5-bromo-1-tert-butyl-1H-pyrazole-4-carboxamide (100 mg, 0.41 mmol), trans-2-(4-methoxyphenyl)vinylboronic acid (108 mg, 0.61 mmol), S-phos (3.34 mg, 8.13 μmol), palladium(II) acetate (0.912 mg, 4.06 μmol) and tripotassium phosphate (173 mg, 0.81 mmol) in THF (2 mL) was stirred under an argon atmosphere at 40° C. for 14 hr. Water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (solvent gradient; 3→100% ethyl acetate/hexane) to give (E)-1-tert-butyl-5-(4-methoxystyryl)-1H-pyrazole-4-carboxamide (20 mg, 0.067 mmol, 16.4%) as a white powder.
