To a 500 mL round-bottomed flask was added 3-bromobenzaldehyde (6.44 g, 35.0 mmol, 1.00 eq.), morpholine (9.13 g, 105 mmol, 3.00 eq.), tris(dibenzylideneacetone)dipalladium (1.81 g, 1.75 mmol, 0.05 eq.), dicyclohexyl(2',6'-diisopropoxybiphenyl-2-yl)phosphine ( 3.26 g, 7.00 mmol, 0.20 equiv), cesium carbonate (34.2 g, 105 mmol) under nitrogen, 3.00 equiv), toluene (100 mL). The resulting solution was stirred overnight at 90C and quenched with water (50 mL). The resulting solution was extracted with dichloromethane (3 x 200 mL), the organic layers were combined, washed with brine (3 x 100 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was chromatographed on a silica gel column with ethyl acetate/petroleum ether (3/17) to give 3-morpholino benzaldehyde (2.10 g, 32% yield) as a yellow oil.
