N-Formylsaccharin

Typical Procedure (entry 1):
Pd(OAc)₂ (10.1 mg, 0.045 mmol, 3.0 mol%), DPPB (28.8 mg, 0.068 mmol, 4.5 mol%), N-formylsaccharin (475 mg, 2.25 mmol, 1.5eq.), and Na₂CO₃ (238 mg, 2.25 mmol, 1.5eq.) are added to a 30 mL test tube, which is then evacuated and backfilled three times with N₂. A solution of bromobenzene (158 µL, 1.50 mmol) and Et₃SiH (311 µL, 1.95 mmol, 1.3eq.) in DMF (6 mL) is added to the test tube under N₂. The tube is immediately sealed and the mixture is stirred efficiently for 10 min at rt. The mixture is subsequently warmed to 75 °C and stirred for a further 16 h. The reaction mixture is cooled to rt, then diluted with Et₂O (15 mL), and washed with H₂O (15 mL). The aqueous layer is extracted two times with Et₂O (15 mL). The combined organic layer is dried over MgSO₄, filtered, and concentrated. The obtained residue is purified by flash column chromatography on silica gel (eluent: 3–5% Et₂O in n-pentane) to provide benzaldehyde as a colorless oil (132 mg, 83%).