反应详情

Under argon atmosphere, a solution of tert-butyl 6-bromo-2H-1-benzopyran-3-carboxylate (5.00 g), 4-methylphenyl borate (2.62 g) and potassium carbonate (4.44 g) in toluene-ethanol-water (160-16-16 ml) was stirred at room temperature for 1 hour. To the reaction mixture was added tetrakistriphenylphosphinepalladium (0.56 g), and the mixture was refluxed for 14 hours and cooled to room temperature. The organic layer was washed with saturated sodium chloride solution, dried with magnesium sulfate and concentrated. The residue was separated and purified with column chromatography (ethyl acetate/hexane=1:19) to give pale yellow crystals, which were recrystallized from ethanol to give tert-butyl 6-(4-methylphenyl)-2H-1-benzopyran-3-carboxylate (3.84 g) as pale yellow crystals.

1. temperaturethe mixture was refluxed for 14 hours
2. washThe organic layer was washed with saturated sodium chloride solution
3. dry with materialdried with magnesium sulfate
4. concentrationconcentrated
5. customThe residue was separated
6. custompurified with column chromatography (ethyl acetate/hexane=1:19)
7. customto give pale yellow crystals, which
8. customwere recrystallized from ethanol