1,2-Dimethoxyethane → 4-Ethenyl-2-hydroxybenzoic acid

Beteiligte Stoffe

Reaktionsschritte

A round-bottom flask is charged with 2-Hydroxy-4-iodo-benzoic acid methyl ester, 26-01 (12.0 g, 43.2 mmol), 2,4,6-Trivinyl-cyclotriboroxane-pyridine complex (11.4 g, 47.5 mmol), tetrakis(triphenylphosphine) palladium (2.49 g, 2.16 mmol), 2.0 M aqueous solution of sodium carbonate (25.9 mL, 51.7 mmol), and 1,2-dimethoxyethane (50 mL), deoxygenated by alternating between vacuum and argon (3×), and refluxed under argon pressure for 3 h, and then stirred 18 h at ambient temperature. Volatiles are stripped in vacuo, the residue is suspended in 1N HCl (800 mL) and extracted with EtOAc (600 mL, 300 mL, and then 300 mL). The combined organic extracts are washed brine, dried over NaSO4, and purified by chromatography (silica gel, 5-30% EtOAc in heptane) to afford 2-Hydroxy-4-vinyl-benzoic acid, 26-02 (3.70 g) and 2-Hydroxy-4-vinyl-benzoic acid methyl ester (0.300 g).

Herkunft & Nachweise