Di-tert-butyl 2-fluoromalonate

Di-tert-butyl 2-fluoromalonate

Di-tert-butylmalonate (12.0 g, 55 mmol) and copper nitrate catalyst (1.16 g, 5 mmol) were dissolved in acetonitrile (50 mL), placed in a fluorination vessel and the mixture was cooled to 0–5 °C. After purging the system with N₂ for 5 minutes, fluorine gas (20% v/v in N₂, 44 mL min⁻¹, 60 mmol) was introduced for 5 h. After purging with nitrogen for 10 minutes, the solvent was removed under reduced pressure and the residue was partitioned between water (10 mL) and ethyl acetate (25 mL). The aqueous phase was extracted with ethyl acetate (25 mL) then the combined organic layer was washed with saturated brine (10 mL). After drying over sodium sulphate, the solvent was evaporated under reduced pressure to leave di-tert-butyl 2-fluoromalonate (12.57 g, 96% yield, 97% purity) as a colourless liquid;

IR (neat, cm⁻¹) 2980, 1744, 1369, 1252, 1143;  

δ_H (CDCl₃, 400 MHz) 1.49 (18H, s, CH₃), 5.01 (1H, d, ²J_HF 48.9, CHF);  

δ_F (CDCl₃, 376 MHz): −193.79 (d, ²J_HF 48.9, CH–F); δ_C (CDCl₃, 100 MHz) 27.95 (CH₃), 84.01 (C–CH₃), 85.97 (d, ¹J_CF 196.5, C–F), 163.32 (d, ²J_CF 24.5, CO);  

m/z (EI⁺) 162 (20%, [M − OtBu + H]⁺), 57 (100%, [tBu]⁺).


http://pubs.rsc.org/en/content/articlehtml/2015/gc/c5gc00402k
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