Dimethylformamide → 2,4,6-Trichlorobenzaldehyde

2,4,6-Trichlorobenzaldehyde was prepared according to the procedure outlined in Synthesis 2008, 279. To a solution of 1,3,5-trichlorobenzene (10.0 g, 55.1 mmol) in THF (200 ml) at −78° C. was slowly added n-BuLi (1.6 M in hexanes, 34.4 ml, 55.1 mmol) over 20 min. The reaction mixture was stirred at −78° C. for 30 min then DMF (7.5 ml, 96.4 mmol) was added dropwise. The reaction was stirred at −78° C. for an additional 1.5 h then quenched with 3 N HCl (200 ml) and warmed to room temperature. The mixture was extracted with EtOAc. The organic layer was washed with sat NaHCO3 and brine then dried over MgSO4 and concentrated to afford 10.7 g (93%) of 2,4,6-trichlorobenzaldehyde as a white solid.