General procedure for the synthesis of 4-(4-morpholinyl)phenylboronic acid pinacol ester from 4-(4-bromophenyl)morpholine and pinacolborane: To a solution of 4-(4-bromophenyl)morpholine (20 g, 82.64 mmol) in dioxane (200 ml) were added pinacolborane (13.2 g, 99.17 mmol), dichlorobis(triphenylphosphine)palladium(II) (3 g 4.13 mmol) and triethylamine (34.5 ml, 247.93 mmol). The reaction mixture was heated under reflux conditions for 4 hours. After completion of the reaction, the mixture was poured into water. After extraction with dichloromethane, the organic phase was dried with anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: dichloromethane) to afford 4-(4-morpholinyl)benzeneboronic acid pinacol ester as an orange oil, which crystallized after cooling (19.98 g, 83.94% yield); APCI-MS m/z 289.07 ([M+H]+).
