Dimethylformamide → 2-Chloro-6-fluoro-3-methylbenzaldehyde

Participants

Reaction Conditions

Reaction Steps

A solution of 1.3M s-butyl lithium in cyclohexane (75 mL, 98 mmol) is added to a dry-ice/acetone cooled solution of TMEDA (9.67 g, 83 mmol) in THF (90 mL), maintaining the internal reaction temperature <-70° C. The reaction mixture is cooled and maintained at ≤-80° C. with an ether/liquid nitrogen bath while a solution of 2-chloro-4-fluorotoluene (10 g, 69 mmol) in THF (10 mL) is added dropwise. The resulting reaction mixture is stirred with dry-ice/acetone cooling for 1h, then is cannulated into an ether/liquid nitrogen cooled and mechanically stirred solution of DMF (25.1 g, 345 mmol) in THF (50 mL). The resulting mixture is warmed to -30° C. and partitioned between dilute aqueous HCl and ether. The organic solution is washed with aqueous NaHCO3, dried (MgSO4), and concentrated and triturated with hexanes to afford 2-fluoro-5-methyl-6-chlorobenzaldehyde as a crystalline solid.

Provenance & Evidence