反应详情

2,4,6-Trimethyl-cyclotriboroxane (6.99 ml, 50.0 mmol) was added to a stirred suspension of methyl 2-amino-5-bromo-3-iodo-benzoate (Preparation #11a, 15.5 g, 43.6 mmol), [1,1′-bis(diphenylphosphino)-ferrocene)dichloropalladium(II) 1:1 complexed with dichloromethane (1.67 g, 2.05 mmol) and cesium carbonate (42.9 g, 132 mmol) in 1,4-dioxane (200 mL) under N2. After about 4 hours at about 90° C. additional 2,4,6-trimethyl-cyclotriboroxane (1.00 ml, 7.15 mmol) was added and the reaction was continued with heating for about 2 more hours. The reaction was cooled, filtered through a short pad of silica gel and concentrated to afford an oil. The crude product was purified by flash chromatography over silica gel using heptane:EtOAc (92:8) as the eluent to yield methyl 2-amino-5-bromo-3-methyl-benzoate (5.9 g, 55%) as a pale yellow solid; RP HPLC (Table 1, Method e) Rt=2.72, m/z: (MH)+ 244/246.

1. temperaturewith heating for about 2 more hours
2. temperatureThe reaction was cooled
3. filtrationfiltered through a short pad of silica gel
4. concentrationconcentrated
5. customto afford an oil
6. customThe crude product was purified by flash chromatography over silica gel