Sulfuric Acid → Tert-butyl 3,5-difluorobenzoate

Participants

Reaction Steps

3,5-Difluorobenzoic acid (25 g, 0.158 mol) was dissolved in DCM (150 mL) and dioxane (50 mL). The mixture was transferred into a stainless steel autoclave. Concentrated sulfuric acid (3.6 mL) was added, followed by isobutene (100 mL). The mixture was kept in the autoclave for 5 days. Excess isobutene and the solvents were removed under reduced pressure, the mixture diluted with EtOAc and washed with water, saturated aqueous sodium hydrogen carbonate and brine. Drying and evaporation gave a dark-yellow oil, which was purified by kugelrohr distillation (80–100° C., 1.0 mbar) to give tert-butyl-3,5-difluorobenzoate (27.51, g, 81% ) as a colorless solid.

Provenance & Evidence