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;
δH (CDCl3, 400 MHz) 1.49 (18H, s, CH3), 5.01 (1H, d, 2JHF 48.9, CHF);
δF (CDCl3, 376 MHz): −193.79 (d, 2JHF 48.9, CH–F); δC (CDCl3, 100 MHz) 27.95 (CH3), 84.01 (C–CH3), 85.97 (d, 1JCF 196.5, C–F), 163.32 (d, 2JCF 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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