反应详情

温度

100 °C

A mixture of t-butyl 5-bromopicolinate (581 mg, 2.25 mmol), 4-hydroxy-2,2-dimethyl-2,3-dihydro-benzofuran-6-carboxylic acid methyl ester (3e) (500 mg, 2.25 mmol), K3PO4 (956 mg, 4.50 mmol), 2-di-t-butylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphyl (96 mg, 0.225 mmol), and Pd(OAc)2 (51 mg, 0.225 mmol) in toluene (10 mL) was heated to 100° C. in a microwave for 3 h, cooled to room temperature, filtered through celite, washed with EtOAc, concentrated, and purified by Biotage column chromatography with 15-30% EtOAc in hexanes to give 26 mg of 5-(6-Methoxycarbonyl-2,2-dimethyl-2,3-dihydro-benzofuran-4-yloxy)-pyridine-2-carboxylic acid tert-butyl ester and 400 mg mixture of the title compound with ˜40% of 4-hydroxy-2,2-dimethyl-2,3-dihydrobenzofuran-6-carboxylic acid methyl ester as a yellow foam. 1H NMR (400 MHz, CDCl3) δ 8.47 (d, J=2.53 Hz, 1 H) 8.05 (d, J=8.84 Hz, 1 H) 7.23-7.36 (m, 2 H) 7.19 (d, J=1.26 Hz, 1 H) 3.87 (s, 3 H) 2.89 (s, 2 H) 1.64 (s, 9 H) 1.48 (s, 6 H); LCMS for C22H25NO6 m/z 344.00 (M-tBu+H+).

1. temperaturecooled to room temperature
2. filtrationfiltered through celite
3. washwashed with EtOAc
4. concentrationconcentrated
5. custompurified by Biotage column chromatography with 15-30% EtOAc in hexanes