p-Toluenesulfonic acid → Allyl 3-fluoro-5-nitrobenzoate

Participants

Reaction Steps

3-Fluoro-5-nitrobenzoic acid (3 g, 16.2 mM), p-toluene-sulfonic acid (1.54 g, 8.1 mM), and allyl alcohol (50 ml) were heated to reflux, passing the distillate through 3a molecular sieves, for 16 hours. After cooling, the mixture was neutralised with triethylamine, and solvent removed. The residue was dissolved in ethyl acetate, washed with 2M hydrochloric acid, aqueous NaHCO3, and brine, and dried over MgSO4. Crude product was purified by chromatography on silica, using a gradient elution from dichloromethane to ethyl acetate/dichloromethane (3:1), to give allyl 3-fluoro-5-nitrobenzoate. Nmr (CDCl3): δ 4.89 (dt, 2H); 5.33-5.49 (m, 2H); 5.95-6.15 (m, 1H); 8.11 (m, 2H); 8.70 (t, 1H).

Provenance & Evidence