4-(4-Bromo-2-nitrophenyl)morpholine (500 mg, 1.74 mmol), morpholine (0.3 mL, 3.48 mmol), Pd2dba3 (112 mg, 0.12 mmol), X-Phos (125 mg, 261 μmol) and sodium tert-butoxide were suspended in toluene (71.0 mL, 666 mmol) and heated at reflux for 2 h. After this time the reaction was cooled to rt and evaporated in vacuo. The residue was taken up in EtOAc (80 mL) and washed with NaHCO3 (satd aq. solution, 40 mL) and brine (40 mL). The separated organic layer was dried over magnesium sulfate, filtered and evaporated in vacuo. Column chromatography (hexanes:EtOAc, 1:0 to 1:2) gave 4,4′-(2-nitro-1,4-phenylene)dimorpholine. Mass Spectrum (ESI) m/e=294.2 (M+1).
